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 TCSH(1)                       Astron 6.20.00                        TCSH(1)
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 NAME
      tcsh - C shell with file name completion and command line editing

 SYNOPSIS
      tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
      tcsh -l

 DESCRIPTION
      tcsh is an enhanced but completely compatible version of the Berkeley
      UNIX C shell, csh(1).  It is a command language interpreter usable
      both as an interactive login shell and a shell script command
      processor.  It includes a command-line editor (see The command-line
      editor), programmable word completion (see Completion and listing),
      spelling correction (see Spelling correction), a history mechanism
      (see History substitution), job control (see Jobs) and a C-like
      syntax.  The NEW FEATURES section describes major enhancements of tcsh
      over csh(1).  Throughout this manual, features of tcsh not found in
      most csh(1) implementations (specifically, the 4.4BSD csh) are labeled
      with `(+)', and features which are present in csh(1) but not usually
      documented are labeled with `(u)'.

    Argument list processing
      If the first argument (argument 0) to the shell is `-' then it is a
      login shell.  A login shell can be also specified by invoking the
      shell with the -l flag as the only argument.

      The rest of the flag arguments are interpreted as follows:

      -b  Forces a ``break'' from option processing, causing any further
          shell arguments to be treated as non-option arguments.  The
          remaining arguments will not be interpreted as shell options.
          This may be used to pass options to a shell script without
          confusion or possible subterfuge.  The shell will not run a set-
          user ID script without this option.

      -c  Commands are read from the following argument (which must be
          present, and must be a single argument), stored in the command
          shell variable for reference, and executed.  Any remaining
          arguments are placed in the argv shell variable.

      -d  The shell loads the directory stack from ~/.cshdirs as described
          under Startup and shutdown, whether or not it is a login shell.
          (+)

      -Dname[=value]
          Sets the environment variable name to value. (Domain/OS only) (+)

      -e  The shell exits if any invoked command terminates abnormally or
          yields a non-zero exit status.





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      -f  The shell does not load any resource or startup files, or perform
          any command hashing, and thus starts faster.

      -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

      -i  The shell is interactive and prompts for its top-level input, even
          if it appears to not be a terminal.  Shells are interactive
          without this option if their inputs and outputs are terminals.

      -l  The shell is a login shell.  Applicable only if -l is the only
          flag specified.

      -m  The shell loads ~/.tcshrc even if it does not belong to the
          effective user.  Newer versions of su(1) can pass -m to the shell.
          (+)

      -n  The shell parses commands but does not execute them.  This aids in
          debugging shell scripts.

      -q  The shell accepts SIGQUIT (see Signal handling) and behaves when
          it is used under a debugger.  Job control is disabled. (u)

      -s  Command input is taken from the standard input.

      -t  The shell reads and executes a single line of input.  A `\' may be
          used to escape the newline at the end of this line and continue
          onto another line.

      -v  Sets the verbose shell variable, so that command input is echoed
          after history substitution.

      -x  Sets the echo shell variable, so that commands are echoed
          immediately before execution.

      -V  Sets the verbose shell variable even before executing ~/.tcshrc.

      -X  Is to -x as -V is to -v.

      --help
          Print a help message on the standard output and exit. (+)

      --version
          Print the version/platform/compilation options on the standard
          output and exit.  This information is also contained in the
          version shell variable. (+)

      After processing of flag arguments, if arguments remain but none of
      the -c, -i, -s, or -t options were given, the first argument is taken
      as the name of a file of commands, or ``script'', to be executed.  The
      shell opens this file and saves its name for possible resubstitution
      by `$0'.  Because many systems use either the standard version 6 or



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      version 7 shells whose shell scripts are not compatible with this
      shell, the shell uses such a `standard' shell to execute a script
      whose first character is not a `#', i.e., that does not start with a
      comment.

      Remaining arguments are placed in the argv shell variable.

    Startup and shutdown
      A login shell begins by executing commands from the system files
      /etc/csh.cshrc and /etc/csh.login.  It then executes commands from
      files in the user's home directory: first ~/.tcshrc (+) or, if
      ~/.tcshrc is not found, ~/.cshrc, then the contents of ~/.history (or
      the value of the histfile shell variable) are loaded into memory, then
      ~/.login, and finally ~/.cshdirs (or the value of the dirsfile shell
      variable) (+).  The shell may read /etc/csh.login before instead of
      after /etc/csh.cshrc, and ~/.login before instead of after ~/.tcshrc
      or ~/.cshrc and ~/.history, if so compiled; see the version shell
      variable. (+)

      Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on
      startup.

      For examples of startup files, please consult
      http://tcshrc.sourceforge.net.

      Commands like stty(1) and tset(1), which need be run only once per
      login, usually go in one's ~/.login file.  Users who need to use the
      same set of files with both csh(1) and tcsh can have only a ~/.cshrc
      which checks for the existence of the tcsh shell variable (q.v.)
      before using tcsh-specific commands, or can have both a ~/.cshrc and a
      ~/.tcshrc which sources (see the builtin command) ~/.cshrc.  The rest
      of this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
      not found, ~/.cshrc'.

      In the normal case, the shell begins reading commands from the
      terminal, prompting with `> '.  (Processing of arguments and the use
      of the shell to process files containing command scripts are described
      later.) The shell repeatedly reads a line of command input, breaks it
      into words, places it on the command history list, parses it and
      executes each command in the line.

      One can log out by typing `^D' on an empty line, `logout' or `login'
      or via the shell's autologout mechanism (see the autologout shell
      variable).  When a login shell terminates it sets the logout shell
      variable to `normal' or `automatic' as appropriate, then executes
      commands from the files /etc/csh.logout and ~/.logout.  The shell may
      drop DTR on logout if so compiled; see the version shell variable.

      The names of the system login and logout files vary from system to
      system for compatibility with different csh(1) variants; see FILES.




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    Editing
      We first describe The command-line editor.  The Completion and listing
      and Spelling correction sections describe two sets of functionality
      that are implemented as editor commands but which deserve their own
      treatment.  Finally, Editor commands lists and describes the editor
      commands specific to the shell and their default bindings.

    The command-line editor (+)
      Command-line input can be edited using key sequences much like those
      used in emacs(1) or vi(1).  The editor is active only when the edit
      shell variable is set, which it is by default in interactive shells.
      The bindkey builtin can display and change key bindings.
      emacs(1)-style key bindings are used by default (unless the shell was
      compiled otherwise; see the version shell variable), but bindkey can
      change the key bindings to vi(1)-style bindings en masse.

      The shell always binds the arrow keys (as defined in the TERMCAP
      environment variable) to

          down    down-history
          up      up-history
          left    backward-char
          right   forward-char

      unless doing so would alter another single-character binding.  One can
      set the arrow key escape sequences to the empty string with settc to
      prevent these bindings.  The ANSI/VT100 sequences for arrow keys are
      always bound.

      Other key bindings are, for the most part, what emacs(1) and vi(1)
      users would expect and can easily be displayed by bindkey, so there is
      no need to list them here.  Likewise, bindkey can list the editor
      commands with a short description of each.  Certain key bindings have
      different behavior depending if emacs(1) or vi(1) style bindings are
      being used; see vimode for more information.

      Note that editor commands do not have the same notion of a ``word'' as
      does the shell.  The editor delimits words with any non-alphanumeric
      characters not in the shell variable wordchars, while the shell
      recognizes only whitespace and some of the characters with special
      meanings to it, listed under Lexical structure.

    Completion and listing (+)
      The shell is often able to complete words when given a unique
      abbreviation.  Type part of a word (for example `ls /usr/lost') and
      hit the tab key to run the complete-word editor command.  The shell
      completes the filename `/usr/lost' to `/usr/lost+found/', replacing
      the incomplete word with the complete word in the input buffer.  (Note
      the terminal `/'; completion adds a `/' to the end of completed
      directories and a space to the end of other completed words, to speed
      typing and provide a visual indicator of successful completion.  The



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      addsuffix shell variable can be unset to prevent this.) If no match is
      found (perhaps `/usr/lost+found' doesn't exist), the terminal bell
      rings.  If the word is already complete (perhaps there is a
      `/usr/lost' on your system, or perhaps you were thinking too far ahead
      and typed the whole thing) a `/' or space is added to the end if it
      isn't already there.

      Completion works anywhere in the line, not at just the end; completed
      text pushes the rest of the line to the right.  Completion in the
      middle of a word often results in leftover characters to the right of
      the cursor that need to be deleted.

      Commands and variables can be completed in much the same way.  For
      example, typing `em[tab]' would complete `em' to `emacs' if emacs were
      the only command on your system beginning with `em'.  Completion can
      find a command in any directory in path or if given a full pathname.
      Typing `echo $ar[tab]' would complete `$ar' to `$argv' if no other
      variable began with `ar'.

      The shell parses the input buffer to determine whether the word you
      want to complete should be completed as a filename, command or
      variable.  The first word in the buffer and the first word following
      `;', `|', `|&', `&&' or `||' is considered to be a command.  A word
      beginning with `$' is considered to be a variable.  Anything else is a
      filename.  An empty line is `completed' as a filename.

      You can list the possible completions of a word at any time by typing
      `^D' to run the delete-char-or-list-or-eof editor command.  The shell
      lists the possible completions using the ls-F builtin (q.v.) and
      reprints the prompt and unfinished command line, for example:

          > ls /usr/l[^D]
          lbin/       lib/        local/      lost+found/
          > ls /usr/l

      If the autolist shell variable is set, the shell lists the remaining
      choices (if any) whenever completion fails:

          > set autolist
          > nm /usr/lib/libt[tab]
          libtermcap.a@ libtermlib.a@
          > nm /usr/lib/libterm

      If autolist is set to `ambiguous', choices are listed only when
      completion fails and adds no new characters to the word being
      completed.

      A filename to be completed can contain variables, your own or others'
      home directories abbreviated with `~' (see Filename substitution) and
      directory stack entries abbreviated with `=' (see Directory stack
      substitution).  For example,



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          > ls ~k[^D]
          kahn    kas     kellogg
          > ls ~ke[tab]
          > ls ~kellogg/

      or

          > set local = /usr/local
          > ls $lo[tab]
          > ls $local/[^D]
          bin/ etc/ lib/ man/ src/
          > ls $local/

      Note that variables can also be expanded explicitly with the expand-
      variables editor command.

      delete-char-or-list-or-eof lists at only the end of the line; in the
      middle of a line it deletes the character under the cursor and on an
      empty line it logs one out or, if ignoreeof is set, does nothing.
      `M-^D', bound to the editor command list-choices, lists completion
      possibilities anywhere on a line, and list-choices (or any one of the
      related editor commands that do or don't delete, list and/or log out,
      listed under delete-char-or-list-or-eof) can be bound to `^D' with the
      bindkey builtin command if so desired.

      The complete-word-fwd and complete-word-back editor commands (not
      bound to any keys by default) can be used to cycle up and down through
      the list of possible completions, replacing the current word with the
      next or previous word in the list.

      The shell variable fignore can be set to a list of suffixes to be
      ignored by completion.  Consider the following:

          > ls
          Makefile        condiments.h~   main.o          side.c
          README          main.c          meal            side.o
          condiments.h    main.c~
          > set fignore = (.o \~)
          > emacs ma[^D]
          main.c   main.c~  main.o
          > emacs ma[tab]
          > emacs main.c

      `main.c~' and `main.o' are ignored by completion (but not listing),
      because they end in suffixes in fignore.  Note that a `\' was needed
      in front of `~' to prevent it from being expanded to home as described
      under Filename substitution.  fignore is ignored if only one
      completion is possible.

      If the complete shell variable is set to `enhance', completion 1)
      ignores case and 2) considers periods, hyphens and underscores (`.',



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      `-' and `_') to be word separators and hyphens and underscores to be
      equivalent.  If you had the following files

          comp.lang.c      comp.lang.perl   comp.std.c++
          comp.lang.c++    comp.std.c

      and typed `mail -f c.l.c[tab]', it would be completed to `mail -f
      comp.lang.c', and ^D would list `comp.lang.c' and `comp.lang.c++'.
      `mail -f c..c++[^D]' would list `comp.lang.c++' and `comp.std.c++'.
      Typing `rm a--file[^D]' in the following directory

          A_silly_file    a-hyphenated-file    another_silly_file

      would list all three files, because case is ignored and hyphens and
      underscores are equivalent.  Periods, however, are not equivalent to
      hyphens or underscores.

      If the complete shell variable is set to `Enhance', completion ignores
      case and differences between a hyphen and an underscore word separator
      only when the user types a lowercase character or a hyphen.  Entering
      an uppercase character or an underscore will not match the
      corresponding lowercase character or hyphen word separator. Typing `rm
      a--file[^D]' in the directory of the previous example would still list
      all three files, but typing `rm A--file' would match only
      `A_silly_file' and typing `rm a__file[^D]' would match just
      `A_silly_file' and `another_silly_file' because the user explicitly
      used an uppercase or an underscore character.

      Completion and listing are affected by several other shell variables:
      recexact can be set to complete on the shortest possible unique match,
      even if more typing might result in a longer match:

          > ls
          fodder   foo      food     foonly
          > set recexact
          > rm fo[tab]

      just beeps, because `fo' could expand to `fod' or `foo', but if we
      type another `o',

          > rm foo[tab]
          > rm foo

      the completion completes on `foo', even though `food' and `foonly'
      also match.  autoexpand can be set to run the expand-history editor
      command before each completion attempt, autocorrect can be set to
      spelling-correct the word to be completed (see Spelling correction)
      before each completion attempt and correct can be set to complete
      commands automatically after one hits `return'.  matchbeep can be set
      to make completion beep or not beep in a variety of situations, and
      nobeep can be set to never beep at all.  nostat can be set to a list



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      of directories and/or patterns that match directories to prevent the
      completion mechanism from stat(2)ing those directories.  listmax and
      listmaxrows can be set to limit the number of items and rows
      (respectively) that are listed without asking first.
      recognize_only_executables can be set to make the shell list only
      executables when listing commands, but it is quite slow.

      Finally, the complete builtin command can be used to tell the shell
      how to complete words other than filenames, commands and variables.
      Completion and listing do not work on glob-patterns (see Filename
      substitution), but the list-glob and expand-glob editor commands
      perform equivalent functions for glob-patterns.

    Spelling correction (+)
      The shell can sometimes correct the spelling of filenames, commands
      and variable names as well as completing and listing them.

      Individual words can be spelling-corrected with the spell-word editor
      command (usually bound to M-s and M-S) and the entire input buffer
      with spell-line (usually bound to M-$).  The correct shell variable
      can be set to `cmd' to correct the command name or `all' to correct
      the entire line each time return is typed, and autocorrect can be set
      to correct the word to be completed before each completion attempt.

      When spelling correction is invoked in any of these ways and the shell
      thinks that any part of the command line is misspelled, it prompts
      with the corrected line:

          > set correct = cmd
          > lz /usr/bin
          CORRECT>ls /usr/bin (y|n|e|a)?

      One can answer `y' or space to execute the corrected line, `e' to
      leave the uncorrected command in the input buffer, `a' to abort the
      command as if `^C' had been hit, and anything else to execute the
      original line unchanged.

      Spelling correction recognizes user-defined completions (see the
      complete builtin command).  If an input word in a position for which a
      completion is defined resembles a word in the completion list,
      spelling correction registers a misspelling and suggests the latter
      word as a correction.  However, if the input word does not match any
      of the possible completions for that position, spelling correction
      does not register a misspelling.

      Like completion, spelling correction works anywhere in the line,
      pushing the rest of the line to the right and possibly leaving extra
      characters to the right of the cursor.

    Editor commands (+)
      `bindkey' lists key bindings and `bindkey -l' lists and briefly



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      describes editor commands.  Only new or especially interesting editor
      commands are described here.  See emacs(1) and vi(1) for descriptions
      of each editor's key bindings.

      The character or characters to which each command is bound by default
      is given in parentheses.  `^character' means a control character and
      `M-character' a meta character, typed as escape-character on terminals
      without a meta key.  Case counts, but commands that are bound to
      letters by default are bound to both lower- and uppercase letters for
      convenience.

      backward-char (^B, left)
              Move back a character.  Cursor behavior modified by vimode.

      backward-delete-word (M-^H, M-^?)
              Cut from beginning of current word to cursor - saved in cut
              buffer.  Word boundary behavior modified by vimode.

      backward-word (M-b, M-B)
              Move to beginning of current word.  Word boundary and cursor
              behavior modified by vimode.

      beginning-of-line (^A, home)
              Move to beginning of line.  Cursor behavior modified by
              vimode.

      capitalize-word (M-c, M-C)
              Capitalize the characters from cursor to end of current word.
              Word boundary behavior modified by vimode.

      complete-word (tab)
              Completes a word as described under Completion and listing.

      complete-word-back (not bound)
              Like complete-word-fwd, but steps up from the end of the list.

      complete-word-fwd (not bound)
              Replaces the current word with the first word in the list of
              possible completions.  May be repeated to step down through
              the list.  At the end of the list, beeps and reverts to the
              incomplete word.

      complete-word-raw (^X-tab)
              Like complete-word, but ignores user-defined completions.

      copy-prev-word (M-^_)
              Copies the previous word in the current line into the input
              buffer.  See also insert-last-word.  Word boundary behavior
              modified by vimode.





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      dabbrev-expand (M-/)
              Expands the current word to the most recent preceding one for
              which the current is a leading substring, wrapping around the
              history list (once) if necessary.  Repeating dabbrev-expand
              without any intervening typing changes to the next previous
              word etc., skipping identical matches much like history-
              search-backward does.

      delete-char (not bound)
              Deletes the character under the cursor.  See also delete-
              char-or-list-or-eof.  Cursor behavior modified by vimode.

      delete-char-or-eof (not bound)
              Does delete-char if there is a character under the cursor or
              end-of-file on an empty line.  See also delete-char-or-list-
              or-eof.  Cursor behavior modified by vimode.

      delete-char-or-list (not bound)
              Does delete-char if there is a character under the cursor or
              list-choices at the end of the line.  See also delete-char-
              or-list-or-eof.

      delete-char-or-list-or-eof (^D)
              Does delete-char if there is a character under the cursor,
              list-choices at the end of the line or end-of-file on an empty
              line.  See also those three commands, each of which does only
              a single action, and delete-char-or-eof, delete-char-or-list
              and list-or-eof, each of which does a different two out of the
              three.

      delete-word (M-d, M-D)
              Cut from cursor to end of current word - save in cut buffer.
              Word boundary behavior modified by vimode.

      down-history (down-arrow, ^N)
              Like up-history, but steps down, stopping at the original
              input line.

      downcase-word (M-l, M-L)
              Lowercase the characters from cursor to end of current word.
              Word boundary behavior modified by vimode.

      end-of-file (not bound)
              Signals an end of file, causing the shell to exit unless the
              ignoreeof shell variable (q.v.) is set to prevent this.  See
              also delete-char-or-list-or-eof.

      end-of-line (^E, end)
              Move cursor to end of line.  Cursor behavior modified by
              vimode.




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      expand-history (M-space)
              Expands history substitutions in the current word.  See
              History substitution.  See also magic-space, toggle-literal-
              history and the autoexpand shell variable.

      expand-glob (^X-*)
              Expands the glob-pattern to the left of the cursor.  See
              Filename substitution.

      expand-line (not bound)
              Like expand-history, but expands history substitutions in each
              word in the input buffer.

      expand-variables (^X-$)
              Expands the variable to the left of the cursor.  See Variable
              substitution.

      forward-char (^F, right)
              Move forward one character.  Cursor behavior modified by
              vimode.

      forward-word (M-f, M-F)
              Move forward to end of current word.  Word boundary and cursor
              behavior modified by vimode.

      history-search-backward (M-p, M-P)
              Searches backwards through the history list for a command
              beginning with the current contents of the input buffer up to
              the cursor and copies it into the input buffer.  The search
              string may be a glob-pattern (see Filename substitution)
              containing `*', `?', `[]' or `{}'.  up-history and down-
              history will proceed from the appropriate point in the history
              list.  Emacs mode only.  See also history-search-forward and
              i-search-back.

      history-search-forward (M-n, M-N)
              Like history-search-backward, but searches forward.

      i-search-back (not bound)
              Searches backward like history-search-backward, copies the
              first match into the input buffer with the cursor positioned
              at the end of the pattern, and prompts with `bck: ' and the
              first match.  Additional characters may be typed to extend the
              search, i-search-back may be typed to continue searching with
              the same pattern, wrapping around the history list if
              necessary, (i-search-back must be bound to a single character
              for this to work) or one of the following special characters
              may be typed:

                  ^W      Appends the rest of the word under the cursor to
                          the search pattern.



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                  delete (or any character bound to backward-delete-char)
                          Undoes the effect of the last character typed and
                          deletes a character from the search pattern if
                          appropriate.
                  ^G      If the previous search was successful, aborts the
                          entire search.  If not, goes back to the last
                          successful search.
                  escape  Ends the search, leaving the current line in the
                          input buffer.

              Any other character not bound to self-insert-command
              terminates the search, leaving the current line in the input
              buffer, and is then interpreted as normal input.  In
              particular, a carriage return causes the current line to be
              executed.  See also i-search-fwd and history-search-backward.
              Word boundary behavior modified by vimode.

      i-search-fwd (not bound)
              Like i-search-back, but searches forward.  Word boundary
              behavior modified by vimode.

      insert-last-word (M-_)
              Inserts the last word of the previous input line (`!$') into
              the input buffer.  See also copy-prev-word.

      list-choices (M-^D)
              Lists completion possibilities as described under Completion
              and listing.  See also delete-char-or-list-or-eof and list-
              choices-raw.

      list-choices-raw (^X-^D)
              Like list-choices, but ignores user-defined completions.

      list-glob (^X-g, ^X-G)
              Lists (via the ls-F builtin) matches to the glob-pattern (see
              Filename substitution) to the left of the cursor.

      list-or-eof (not bound)
              Does list-choices or end-of-file on an empty line.  See also
              delete-char-or-list-or-eof.

      magic-space (not bound)
              Expands history substitutions in the current line, like
              expand-history, and inserts a space.  magic-space is designed
              to be bound to the space bar, but is not bound by default.

      normalize-command (^X-?)
              Searches for the current word in PATH and, if it is found,
              replaces it with the full path to the executable.  Special
              characters are quoted.  Aliases are expanded and quoted but
              commands within aliases are not.  This command is useful with



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              commands that take commands as arguments, e.g., `dbx' and `sh
              -x'.

      normalize-path (^X-n, ^X-N)
              Expands the current word as described under the `expand'
              setting of the symlinks shell variable.

      overwrite-mode (unbound)
              Toggles between input and overwrite modes.

      run-fg-editor (M-^Z)
              Saves the current input line and looks for a stopped job where
              the file name portion of its first word is found in the
              editors shell variable.  If editors is not set, then the file
              name portion of the EDITOR environment variable (`ed' if
              unset) and the VISUAL environment variable (`vi' if unset)
              will be used.  If such a job is found, it is restarted as if
              `fg %job' had been typed.  This is used to toggle back and
              forth between an editor and the shell easily.  Some people
              bind this command to `^Z' so they can do this even more
              easily.

      run-help (M-h, M-H)
              Searches for documentation on the current command, using the
              same notion of `current command' as the completion routines,
              and prints it.  There is no way to use a pager; run-help is
              designed for short help files.  If the special alias
              helpcommand is defined, it is run with the command name as a
              sole argument.  Else, documentation should be in a file named
              command.help, command.1, command.6, command.8 or command,
              which should be in one of the directories listed in the HPATH
              environment variable.  If there is more than one help file
              only the first is printed.

      self-insert-command (text characters)
              In insert mode (the default), inserts the typed character into
              the input line after the character under the cursor.  In
              overwrite mode, replaces the character under the cursor with
              the typed character.  The input mode is normally preserved
              between lines, but the inputmode shell variable can be set to
              `insert' or `overwrite' to put the editor in that mode at the
              beginning of each line.  See also overwrite-mode.

      sequence-lead-in (arrow prefix, meta prefix, ^X)
              Indicates that the following characters are part of a multi-
              key sequence.  Binding a command to a multi-key sequence
              really creates two bindings: the first character to sequence-
              lead-in and the whole sequence to the command.  All sequences
              beginning with a character bound to sequence-lead-in are
              effectively bound to undefined-key unless bound to another
              command.



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      spell-line (M-$)
              Attempts to correct the spelling of each word in the input
              buffer, like spell-word, but ignores words whose first
              character is one of `-', `!', `^' or `%', or which contain
              `\', `*' or `?', to avoid problems with switches,
              substitutions and the like.  See Spelling correction.

      spell-word (M-s, M-S)
              Attempts to correct the spelling of the current word as
              described under Spelling correction.  Checks each component of
              a word which appears to be a pathname.

      toggle-literal-history (M-r, M-R)
              Expands or `unexpands' history substitutions in the input
              buffer.  See also expand-history and the autoexpand shell
              variable.

      undefined-key (any unbound key)
              Beeps.

      up-history (up-arrow, ^P)
              Copies the previous entry in the history list into the input
              buffer.  If histlit is set, uses the literal form of the
              entry.  May be repeated to step up through the history list,
              stopping at the top.

      upcase-word (M-u, M-U)
              Uppercase the characters from cursor to end of current word.
              Word boundary behavior modified by vimode.

      vi-beginning-of-next-word (not bound)
              Vi goto the beginning of next word.  Word boundary and cursor
              behavior modified by vimode.

      vi-eword (not bound)
              Vi move to the end of the current word.  Word boundary
              behavior modified by vimode.

      vi-search-back (?)
              Prompts with `?' for a search string (which may be a glob-
              pattern, as with history-search-backward), searches for it and
              copies it into the input buffer.  The bell rings if no match
              is found.  Hitting return ends the search and leaves the last
              match in the input buffer.  Hitting escape ends the search and
              executes the match.  vi mode only.

      vi-search-fwd (/)
              Like vi-search-back, but searches forward.

      which-command (M-?)
              Does a which (see the description of the builtin command) on



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              the first word of the input buffer.

      yank-pop (M-y)
              When executed immediately after a yank or another yank-pop,
              replaces the yanked string with the next previous string from
              the killring. This also has the effect of rotating the
              killring, such that this string will be considered the most
              recently killed by a later yank command. Repeating yank-pop
              will cycle through the killring any number of times.

    Lexical structure
      The shell splits input lines into words at blanks and tabs.  The
      special characters `&', `|', `;', `<', `>', `(', and `)' and the
      doubled characters `&&', `||', `<<' and `>>' are always separate
      words, whether or not they are surrounded by whitespace.

      When the shell's input is not a terminal, the character `#' is taken
      to begin a comment.  Each `#' and the rest of the input line on which
      it appears is discarded before further parsing.

      A special character (including a blank or tab) may be prevented from
      having its special meaning, and possibly made part of another word, by
      preceding it with a backslash (`\') or enclosing it in single (`''),
      double (`"') or backward (``') quotes.  When not otherwise quoted a
      newline preceded by a `\' is equivalent to a blank, but inside quotes
      this sequence results in a newline.

      Furthermore, all Substitutions (see below) except History substitution
      can be prevented by enclosing the strings (or parts of strings) in
      which they appear with single quotes or by quoting the crucial
      character(s) (e.g., `$' or ``' for Variable substitution or Command
      substitution respectively) with `\'.  (Alias substitution is no
      exception: quoting in any way any character of a word for which an
      alias has been defined prevents substitution of the alias.  The usual
      way of quoting an alias is to precede it with a backslash.) History
      substitution is prevented by backslashes but not by single quotes.
      Strings quoted with double or backward quotes undergo Variable
      substitution and Command substitution, but other substitutions are
      prevented.

      Text inside single or double quotes becomes a single word (or part of
      one).  Metacharacters in these strings, including blanks and tabs, do
      not form separate words.  Only in one special case (see Command
      substitution below) can a double-quoted string yield parts of more
      than one word; single-quoted strings never do.  Backward quotes are
      special: they signal Command substitution (q.v.), which may result in
      more than one word.

      Quoting complex strings, particularly strings which themselves contain
      quoting characters, can be confusing.  Remember that quotes need not
      be used as they are in human writing!  It may be easier to quote not



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      an entire string, but only those parts of the string which need
      quoting, using different types of quoting to do so if appropriate.

      The backslash_quote shell variable (q.v.) can be set to make
      backslashes always quote `\', `'', and `"'.  (+) This may make complex
      quoting tasks easier, but it can cause syntax errors in csh(1)
      scripts.

    Substitutions
      We now describe the various transformations the shell performs on the
      input in the order in which they occur.  We note in passing the data
      structures involved and the commands and variables which affect them.
      Remember that substitutions can be prevented by quoting as described
      under Lexical structure.

    History substitution
      Each command, or ``event'', input from the terminal is saved in the
      history list.  The previous command is always saved, and the history
      shell variable can be set to a number to save that many commands.  The
      histdup shell variable can be set to not save duplicate events or
      consecutive duplicate events.

      Saved commands are numbered sequentially from 1 and stamped with the
      time.  It is not usually necessary to use event numbers, but the
      current event number can be made part of the prompt by placing an `!'
      in the prompt shell variable.

      The shell actually saves history in expanded and literal (unexpanded)
      forms.  If the histlit shell variable is set, commands that display
      and store history use the literal form.

      The history builtin command can print, store in a file, restore and
      clear the history list at any time, and the savehist and histfile
      shell variables can be set to store the history list automatically on
      logout and restore it on login.

      History substitutions introduce words from the history list into the
      input stream, making it easy to repeat commands, repeat arguments of a
      previous command in the current command, or fix spelling mistakes in
      the previous command with little typing and a high degree of
      confidence.

      History substitutions begin with the character `!'.  They may begin
      anywhere in the input stream, but they do not nest.  The `!' may be
      preceded by a `\' to prevent its special meaning; for convenience, a
      `!' is passed unchanged when it is followed by a blank, tab, newline,
      `=' or `('.  History substitutions also occur when an input line
      begins with `^'.  This special abbreviation will be described later.
      The characters used to signal history substitution (`!' and `^') can
      be changed by setting the histchars shell variable.  Any input line
      which contains a history substitution is printed before it is



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      executed.

      A history substitution may have an ``event specification'', which
      indicates the event from which words are to be taken, a ``word
      designator'', which selects particular words from the chosen event,
      and/or a ``modifier'', which manipulates the selected words.

      An event specification can be

          n       A number, referring to a particular event
          -n      An offset, referring to the event n before the current
                  event
          #       The current event.  This should be used carefully in
                  csh(1), where there is no check for recursion.  tcsh
                  allows 10 levels of recursion.  (+)
          !       The previous event (equivalent to `-1')
          s       The most recent event whose first word begins with the
                  string s
          ?s?     The most recent event which contains the string s.  The
                  second `?' can be omitted if it is immediately followed by
                  a newline.

      For example, consider this bit of someone's history list:

           9  8:30    nroff -man wumpus.man
          10  8:31    cp wumpus.man wumpus.man.old
          11  8:36    vi wumpus.man
          12  8:37    diff wumpus.man.old wumpus.man

      The commands are shown with their event numbers and time stamps.  The
      current event, which we haven't typed in yet, is event 13.  `!11' and
      `!-2' refer to event 11.  `!!' refers to the previous event, 12.  `!!'
      can be abbreviated `!' if it is followed by `:' (`:' is described
      below).  `!n' refers to event 9, which begins with `n'.  `!?old?' also
      refers to event 12, which contains `old'.  Without word designators or
      modifiers history references simply expand to the entire event, so we
      might type `!cp' to redo the copy command or `!!|more' if the `diff'
      output scrolled off the top of the screen.

      History references may be insulated from the surrounding text with
      braces if necessary.  For example, `!vdoc' would look for a command
      beginning with `vdoc', and, in this example, not find one, but
      `!{v}doc' would expand unambiguously to `vi wumpus.mandoc'.  Even in
      braces, history substitutions do not nest.

      (+) While csh(1) expands, for example, `!3d' to event 3 with the
      letter `d' appended to it, tcsh expands it to the last event beginning
      with `3d'; only completely numeric arguments are treated as event
      numbers.  This makes it possible to recall events beginning with
      numbers.  To expand `!3d' as in csh(1) say `!{3}d'.




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      To select words from an event we can follow the event specification by
      a `:' and a designator for the desired words.  The words of an input
      line are numbered from 0, the first (usually command) word being 0,
      the second word (first argument) being 1, etc.  The basic word
      designators are:

          0       The first (command) word
          n       The nth argument
          ^       The first argument, equivalent to `1'
          $       The last argument
          %       The word matched by an ?s? search
          x-y     A range of words
          -y      Equivalent to `0-y'
          *       Equivalent to `^-$', but returns nothing if the event
                  contains only 1 word
          x*      Equivalent to `x-$'
          x-      Equivalent to `x*', but omitting the last word (`$')

      Selected words are inserted into the command line separated by single
      blanks.  For example, the `diff' command in the previous example might
      have been typed as `diff !!:1.old !!:1' (using `:1' to select the
      first argument from the previous event) or `diff !-2:2 !-2:1' to
      select and swap the arguments from the `cp' command.  If we didn't
      care about the order of the `diff' we might have said `diff !-2:1-2'
      or simply `diff !-2:*'.  The `cp' command might have been written `cp
      wumpus.man !#:1.old', using `#' to refer to the current event.  `!n:-
      hurkle.man' would reuse the first two words from the `nroff' command
      to say `nroff -man hurkle.man'.

      The `:' separating the event specification from the word designator
      can be omitted if the argument selector begins with a `^', `$', `*',
      `%' or `-'.  For example, our `diff' command might have been `diff
      !!^.old !!^' or, equivalently, `diff !!$.old !!$'.  However, if `!!'
      is abbreviated `!', an argument selector beginning with `-' will be
      interpreted as an event specification.

      A history reference may have a word designator but no event
      specification.  It then references the previous command.  Continuing
      our `diff' example, we could have said simply `diff !^.old !^' or, to
      get the arguments in the opposite order, just `diff !*'.

      The word or words in a history reference can be edited, or
      ``modified'', by following it with one or more modifiers, each
      preceded by a `:':

          h       Remove a trailing pathname component, leaving the head.
          t       Remove all leading pathname components, leaving the tail.
          r       Remove a filename extension `.xxx', leaving the root name.
          e       Remove all but the extension.
          u       Uppercase the first lowercase letter.




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          l       Lowercase the first uppercase letter.
          s/l/r/  Substitute l for r.  l is simply a string like r, not a
                  regular expression as in the eponymous ed(1) command.  Any
                  character may be used as the delimiter in place of `/'; a
                  `\' can be used to quote the delimiter inside l and r.
                  The character `&' in the r is replaced by l; `\' also
                  quotes `&'.  If l is empty (``''), the l from a previous
                  substitution or the s from a previous search or event
                  number in event specification is used.  The trailing
                  delimiter may be omitted if it is immediately followed by
                  a newline.
          &       Repeat the previous substitution.
          g       Apply the following modifier once to each word.
          a (+)   Apply the following modifier as many times as possible to
                  a single word.  `a' and `g' can be used together to apply
                  a modifier globally.  With the `s' modifier, only the
                  patterns contained in the original word are substituted,
                  not patterns that contain any substitution result.
          p       Print the new command line but do not execute it.
          q       Quote the substituted words, preventing further
                  substitutions.
          x       Like q, but break into words at blanks, tabs and newlines.

      Modifiers are applied to only the first modifiable word (unless `g' is
      used).  It is an error for no word to be modifiable.

      For example, the `diff' command might have been written as `diff
      wumpus.man.old !#^:r', using `:r' to remove `.old' from the first
      argument on the same line (`!#^').  We could say `echo hello out
      there', then `echo !*:u' to capitalize `hello', `echo !*:au' to say it
      out loud, or `echo !*:agu' to really shout.  We might follow `mail -s
      "I forgot my password" rot' with `!:s/rot/root' to correct the
      spelling of `root' (but see Spelling correction for a different
      approach).

      There is a special abbreviation for substitutions.  `^', when it is
      the first character on an input line, is equivalent to `!:s^'.  Thus
      we might have said `^rot^root' to make the spelling correction in the
      previous example.  This is the only history substitution which does
      not explicitly begin with `!'.

      (+) In csh as such, only one modifier may be applied to each history
      or variable expansion.  In tcsh, more than one may be used, for
      example

          % mv wumpus.man /usr/man/man1/wumpus.1
          % man !$:t:r
          man wumpus

      In csh, the result would be `wumpus.1:r'.  A substitution followed by
      a colon may need to be insulated from it with braces:



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          > mv a.out /usr/games/wumpus
          > setenv PATH !$:h:$PATH
          Bad ! modifier: $.
          > setenv PATH !{-2$:h}:$PATH
          setenv PATH /usr/games:/bin:/usr/bin:.

      The first attempt would succeed in csh but fails in tcsh, because tcsh
      expects another modifier after the second colon rather than `$'.

      Finally, history can be accessed through the editor as well as through
      the substitutions just described.  The up- and down-history, history-
      search-backward and -forward, i-search-back and -fwd, vi-search-back
      and -fwd, copy-prev-word and insert-last-word editor commands search
      for events in the history list and copy them into the input buffer.
      The toggle-literal-history editor command switches between the
      expanded and literal forms of history lines in the input buffer.
      expand-history and expand-line expand history substitutions in the
      current word and in the entire input buffer respectively.

    Alias substitution
      The shell maintains a list of aliases which can be set, unset and
      printed by the alias and unalias commands.  After a command line is
      parsed into simple commands (see Commands) the first word of each
      command, left-to-right, is checked to see if it has an alias.  If so,
      the first word is replaced by the alias.  If the alias contains a
      history reference, it undergoes History substitution (q.v.) as though
      the original command were the previous input line.  If the alias does
      not contain a history reference, the argument list is left untouched.

      Thus if the alias for `ls' were `ls -l' the command `ls /usr' would
      become `ls -l /usr', the argument list here being undisturbed.  If the
      alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
      become `grep bill /etc/passwd'.  Aliases can be used to introduce
      parser metasyntax.  For example, `alias print 'pr \!* | lpr'' defines
      a ``command'' (`print') which pr(1)s its arguments to the line
      printer.

      Alias substitution is repeated until the first word of the command has
      no alias.  If an alias substitution does not change the first word (as
      in the previous example) it is flagged to prevent a loop.  Other loops
      are detected and cause an error.

      Some aliases are referred to by the shell; see Special aliases.

    Variable substitution
      The shell maintains a list of variables, each of which has as value a
      list of zero or more words.  The values of shell variables can be
      displayed and changed with the set and unset commands.  The system
      maintains its own list of ``environment'' variables.  These can be
      displayed and changed with printenv, setenv and unsetenv.




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      (+) Variables may be made read-only with `set -r' (q.v.).  Read-only
      variables may not be modified or unset; attempting to do so will cause
      an error.  Once made read-only, a variable cannot be made writable, so
      `set -r' should be used with caution.  Environment variables cannot be
      made read-only.

      Some variables are set by the shell or referred to by it.  For
      instance, the argv variable is an image of the shell's argument list,
      and words of this variable's value are referred to in special ways.
      Some of the variables referred to by the shell are toggles; the shell
      does not care what their value is, only whether they are set or not.
      For instance, the verbose variable is a toggle which causes command
      input to be echoed.  The -v command line option sets this variable.
      Special shell variables lists all variables which are referred to by
      the shell.

      Other operations treat variables numerically.  The `@' command permits
      numeric calculations to be performed and the result assigned to a
      variable.  Variable values are, however, always represented as (zero
      or more) strings.  For the purposes of numeric operations, the null
      string is considered to be zero, and the second and subsequent words
      of multi-word values are ignored.

      After the input line is aliased and parsed, and before each command is
      executed, variable substitution is performed keyed by `$' characters.
      This expansion can be prevented by preceding the `$' with a `\' except
      within `"'s where it always occurs, and within `''s where it never
      occurs.  Strings quoted by ``' are interpreted later (see Command
      substitution below) so `$' substitution does not occur there until
      later, if at all.  A `$' is passed unchanged if followed by a blank,
      tab, or end-of-line.

      Input/output redirections are recognized before variable expansion,
      and are variable expanded separately.  Otherwise, the command name and
      entire argument list are expanded together.  It is thus possible for
      the first (command) word (to this point) to generate more than one
      word, the first of which becomes the command name, and the rest of
      which become arguments.

      Unless enclosed in `"' or given the `:q' modifier the results of
      variable substitution may eventually be command and filename
      substituted.  Within `"', a variable whose value consists of multiple
      words expands to a (portion of a) single word, with the words of the
      variable's value separated by blanks.  When the `:q' modifier is
      applied to a substitution the variable will expand to multiple words
      with each word separated by a blank and quoted to prevent later
      command or filename substitution.

      The following metasequences are provided for introducing variable
      values into the shell input.  Except as noted, it is an error to
      reference a variable which is not set.



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      $name
      ${name} Substitutes the words of the value of variable name, each
              separated by a blank.  Braces insulate name from following
              characters which would otherwise be part of it.  Shell
              variables have names consisting of letters and digits starting
              with a letter.  The underscore character is considered a
              letter.  If name is not a shell variable, but is set in the
              environment, then that value is returned (but some of the
              other forms given below are not available in this case).
      $name[selector]
      ${name[selector]}
              Substitutes only the selected words from the value of name.
              The selector is subjected to `$' substitution and may consist
              of a single number or two numbers separated by a `-'.  The
              first word of a variable's value is numbered `1'.  If the
              first number of a range is omitted it defaults to `1'.  If the
              last member of a range is omitted it defaults to `$#name'.
              The selector `*' selects all words.  It is not an error for a
              range to be empty if the second argument is omitted or in
              range.
      $0      Substitutes the name of the file from which command input is
              being read.  An error occurs if the name is not known.
      $number
      ${number}
              Equivalent to `$argv[number]'.
      $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

      The `:' modifiers described under History substitution, except for
      `:p', can be applied to the substitutions above.  More than one may be
      used.  (+) Braces may be needed to insulate a variable substitution
      from a literal colon just as with History substitution (q.v.); any
      modifiers must appear within the braces.

      The following substitutions can not be modified with `:' modifiers.

      $?name
      ${?name}
              Substitutes the string `1' if name is set, `0' if it is not.
      $?0     Substitutes `1' if the current input filename is known, `0' if
              it is not.  Always `0' in interactive shells.
      $#name
      ${#name}
              Substitutes the number of words in name.
      $#      Equivalent to `$#argv'.  (+)
      $%name
      ${%name}
              Substitutes the number of characters in name.  (+)
      $%number
      ${%number}
              Substitutes the number of characters in $argv[number].  (+)




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      $?      Equivalent to `$status'.  (+)
      $$      Substitutes the (decimal) process number of the (parent)
              shell.
      $!      Substitutes the (decimal) process number of the last
              background process started by this shell.  (+)
      $_      Substitutes the command line of the last command executed.
              (+)
      $<      Substitutes a line from the standard input, with no further
              interpretation thereafter.  It can be used to read from the
              keyboard in a shell script.  (+) While csh always quotes $<,
              as if it were equivalent to `$<:q', tcsh does not.
              Furthermore, when tcsh is waiting for a line to be typed the
              user may type an interrupt to interrupt the sequence into
              which the line is to be substituted, but csh does not allow
              this.

      The editor command expand-variables, normally bound to `^X-$', can be
      used to interactively expand individual variables.

    Command, filename and directory stack substitution
      The remaining substitutions are applied selectively to the arguments
      of builtin commands.  This means that portions of expressions which
      are not evaluated are not subjected to these expansions.  For commands
      which are not internal to the shell, the command name is substituted
      separately from the argument list.  This occurs very late, after
      input-output redirection is performed, and in a child of the main
      shell.

    Command substitution
      Command substitution is indicated by a command enclosed in ``'.  The
      output from such a command is broken into separate words at blanks,
      tabs and newlines, and null words are discarded.  The output is
      variable and command substituted and put in place of the original
      string.

      Command substitutions inside double quotes (`"') retain blanks and
      tabs; only newlines force new words.  The single final newline does
      not force a new word in any case.  It is thus possible for a command
      substitution to yield only part of a word, even if the command outputs
      a complete line.

      By default, the shell since version 6.12 replaces all newline and
      carriage return characters in the command by spaces.  If this is
      switched off by unsetting csubstnonl, newlines separate commands as
      usual.

    Filename substitution
      If a word contains any of the characters `*', `?', `[' or `{' or
      begins with the character `~' it is a candidate for filename
      substitution, also known as ``globbing''.  This word is then regarded
      as a pattern (``glob-pattern''), and replaced with an alphabetically



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      sorted list of file names which match the pattern.

      In matching filenames, the character `.' at the beginning of a
      filename or immediately following a `/', as well as the character `/'
      must be matched explicitly (unless either globdot or globstar or both
      are set(+)).  The character `*' matches any string of characters,
      including the null string.  The character `?' matches any single
      character. The sequence `[...]' matches any one of the characters
      enclosed. Within `[...]', a pair of characters separated by `-'
      matches any character lexically between the two.

      (+) Some glob-patterns can be negated: The sequence `[^...]' matches
      any single character not specified by the characters and/or ranges of
      characters in the braces.

      An entire glob-pattern can also be negated with `^':

          > echo *
          bang crash crunch ouch
          > echo ^cr*
          bang ouch

      Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or
      `~' (below) are not negated correctly.

      The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'.  Left-
      to-right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
      `/usr/source/s1/oldls.c /usr/source/s1/ls.c'.  The results of matches
      are sorted separately at a low level to preserve this order:
      `../{memo,*box}' might expand to `../memo ../box ../mbox'.  (Note that
      `memo' was not sorted with the results of matching `*box'.) It is not
      an error when this construct expands to files which do not exist, but
      it is possible to get an error from a command to which the expanded
      list is passed.  This construct may be nested.  As a special case the
      words `{', `}' and `{}' are passed undisturbed.

      The character `~' at the beginning of a filename refers to home
      directories.  Standing alone, i.e., `~', it expands to the invoker's
      home directory as reflected in the value of the home shell variable.
      When followed by a name consisting of letters, digits and `-'
      characters the shell searches for a user with that name and
      substitutes their home directory; thus `~ken' might expand to
      `/usr/ken' and `~ken/chmach' to `/usr/ken/chmach'.  If the character
      `~' is followed by a character other than a letter or `/' or appears
      elsewhere than at the beginning of a word, it is left undisturbed.  A
      command like `setenv MANPATH /usr/man:/usr/local/man:~/lib/man' does
      not, therefore, do home directory substitution as one might hope.

      It is an error for a glob-pattern containing `*', `?', `[' or `~',
      with or without `^', not to match any files.  However, only one
      pattern in a list of glob-patterns must match a file (so that, e.g.,



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      `rm *.a *.c *.o' would fail only if there were no files in the current
      directory ending in `.a', `.c', or `.o'), and if the nonomatch shell
      variable is set a pattern (or list of patterns) which matches nothing
      is left unchanged rather than causing an error.

      The globstar shell variable can be set to allow `**' or `***' as a
      file glob pattern that matches any string of characters including `/',
      recursively traversing any existing sub-directories.  For example, `ls
      **.c' will list all the .c files in the current directory tree.  If
      used by itself, it will match zero or more sub-directories (e.g. `ls
      /usr/include/**/time.h' will list any file named `time.h' in the
      /usr/include directory tree; `ls /usr/include/**time.h' will match any
      file in the /usr/include directory tree ending in `time.h'; and `ls
      /usr/include/**time**.h' will match any .h file with `time' either in
      a subdirectory name or in the filename itself).  To prevent problems
      with recursion, the `**' glob-pattern will not descend into a symbolic
      link containing a directory.  To override this, use `***' (+)

      The noglob shell variable can be set to prevent filename substitution,
      and the expand-glob editor command, normally bound to `^X-*', can be
      used to interactively expand individual filename substitutions.

    Directory stack substitution (+)
      The directory stack is a list of directories, numbered from zero, used
      by the pushd, popd and dirs builtin commands (q.v.).  dirs can print,
      store in a file, restore and clear the directory stack at any time,
      and the savedirs and dirsfile shell variables can be set to store the
      directory stack automatically on logout and restore it on login.  The
      dirstack shell variable can be examined to see the directory stack and
      set to put arbitrary directories into the directory stack.

      The character `=' followed by one or more digits expands to an entry
      in the directory stack.  The special case `=-' expands to the last
      directory in the stack.  For example,

          > dirs -v
          0       /usr/bin
          1       /usr/spool/uucp
          2       /usr/accts/sys
          > echo =1
          /usr/spool/uucp
          > echo =0/calendar
          /usr/bin/calendar
          > echo =-
          /usr/accts/sys

      The noglob and nonomatch shell variables and the expand-glob editor
      command apply to directory stack as well as filename substitutions.

    Other substitutions (+)
      There are several more transformations involving filenames, not



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      strictly related to the above but mentioned here for completeness.
      Any filename may be expanded to a full path when the symlinks variable
      (q.v.) is set to `expand'.  Quoting prevents this expansion, and the
      normalize-path editor command does it on demand.  The normalize-
      command editor command expands commands in PATH into full paths on
      demand.  Finally, cd and pushd interpret `-' as the old working
      directory (equivalent to the shell variable owd).  This is not a
      substitution at all, but an abbreviation recognized by only those
      commands.  Nonetheless, it too can be prevented by quoting.

    Commands
      The next three sections describe how the shell executes commands and
      deals with their input and output.

    Simple commands, pipelines and sequences
      A simple command is a sequence of words, the first of which specifies
      the command to be executed.  A series of simple commands joined by `|'
      characters forms a pipeline.  The output of each command in a pipeline
      is connected to the input of the next.

      Simple commands and pipelines may be joined into sequences with `;',
      and will be executed sequentially.  Commands and pipelines can also be
      joined into sequences with `||' or `&&', indicating, as in the C
      language, that the second is to be executed only if the first fails or
      succeeds respectively.

      A simple command, pipeline or sequence may be placed in parentheses,
      `()', to form a simple command, which may in turn be a component of a
      pipeline or sequence.  A command, pipeline or sequence can be executed
      without waiting for it to terminate by following it with an `&'.

    Builtin and non-builtin command execution
      Builtin commands are executed within the shell.  If any component of a
      pipeline except the last is a builtin command, the pipeline is
      executed in a subshell.

      Parenthesized commands are always executed in a subshell.

          (cd; pwd); pwd

      thus prints the home directory, leaving you where you were (printing
      this after the home directory), while

          cd; pwd

      leaves you in the home directory.  Parenthesized commands are most
      often used to prevent cd from affecting the current shell.

      When a command to be executed is found not to be a builtin command the
      shell attempts to execute the command via execve(2).  Each word in the
      variable path names a directory in which the shell will look for the



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      command.  If the shell is not given a -f option, the shell hashes the
      names in these directories into an internal table so that it will try
      an execve(2) in only a directory where there is a possibility that the
      command resides there.  This greatly speeds command location when a
      large number of directories are present in the search path. This
      hashing mechanism is not used:

      1.  If hashing is turned explicitly off via unhash.

      2.  If the shell was given a -f argument.

      3.  For each directory component of path which does not begin with a
          `/'.

      4.  If the command contains a `/'.

      In the above four cases the shell concatenates each component of the
      path vector with the given command name to form a path name of a file
      which it then attempts to execute it. If execution is successful, the
      search stops.

      If the file has execute permissions but is not an executable to the
      system (i.e., it is neither an executable binary nor a script that
      specifies its interpreter), then it is assumed to be a file containing
      shell commands and a new shell is spawned to read it.  The shell
      special alias may be set to specify an interpreter other than the
      shell itself.

      On systems which do not understand the `#!' script interpreter
      convention the shell may be compiled to emulate it; see the version
      shell variable.  If so, the shell checks the first line of the file to
      see if it is of the form `#!interpreter arg ...'.  If it is, the shell
      starts interpreter with the given args and feeds the file to it on
      standard input.

    Input/output
      The standard input and standard output of a command may be redirected
      with the following syntax:

      < name  Open file name (which is first variable, command and filename
              expanded) as the standard input.
      << word Read the shell input up to a line which is identical to word.
              word is not subjected to variable, filename or command
              substitution, and each input line is compared to word before
              any substitutions are done on this input line.  Unless a
              quoting `\', `"', `' or ``' appears in word variable and
              command substitution is performed on the intervening lines,
              allowing `\' to quote `$', `\' and ``'.  Commands which are
              substituted have all blanks, tabs, and newlines preserved,
              except for the final newline which is dropped.  The resultant
              text is placed in an anonymous temporary file which is given



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              to the command as standard input.
      > name
      >! name
      >& name
      >&! name
              The file name is used as standard output.  If the file does
              not exist then it is created; if the file exists, it is
              truncated, its previous contents being lost.

              If the shell variable noclobber is set, then the file must not
              exist or be a character special file (e.g., a terminal or
              `/dev/null') or an error results.  This helps prevent
              accidental destruction of files.  In this case the `!' forms
              can be used to suppress this check.  If notempty is given in
              noclobber, `>' is allowed on empty files; if ask is set, an
              interacive confirmation is presented, rather than an error.

              The forms involving `&' route the diagnostic output into the
              specified file as well as the standard output.  name is
              expanded in the same way as `<' input filenames are.
      >> name
      >>& name
      >>! name
      >>&! name
              Like `>', but appends output to the end of name.  If the shell
              variable noclobber is set, then it is an error for the file
              not to exist, unless one of the `!' forms is given.

      A command receives the environment in which the shell was invoked as
      modified by the input-output parameters and the presence of the
      command in a pipeline.  Thus, unlike some previous shells, commands
      run from a file of shell commands have no access to the text of the
      commands by default; rather they receive the original standard input
      of the shell.  The `<<' mechanism should be used to present inline
      data.  This permits shell command scripts to function as components of
      pipelines and allows the shell to block read its input.  Note that the
      default standard input for a command run detached is not the empty
      file /dev/null, but the original standard input of the shell.  If this
      is a terminal and if the process attempts to read from the terminal,
      then the process will block and the user will be notified (see Jobs).

      Diagnostic output may be directed through a pipe with the standard
      output.  Simply use the form `|&' rather than just `|'.

      The shell cannot presently redirect diagnostic output without also
      redirecting standard output, but `(command > output-file) >& error-
      file' is often an acceptable workaround.  Either output-file or
      error-file may be `/dev/tty' to send output to the terminal.

    Features
      Having described how the shell accepts, parses and executes command



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      lines, we now turn to a variety of its useful features.

    Control flow
      The shell contains a number of commands which can be used to regulate
      the flow of control in command files (shell scripts) and (in limited
      but useful ways) from terminal input.  These commands all operate by
      forcing the shell to reread or skip in its input and, due to the
      implementation, restrict the placement of some of the commands.

      The foreach, switch, and while statements, as well as the if-then-else
      form of the if statement, require that the major keywords appear in a
      single simple command on an input line as shown below.

      If the shell's input is not seekable, the shell buffers up input
      whenever a loop is being read and performs seeks in this internal
      buffer to accomplish the rereading implied by the loop.  (To the
      extent that this allows, backward gotos will succeed on non-seekable
      inputs.)

    Expressions
      The if, while and exit builtin commands use expressions with a common
      syntax.  The expressions can include any of the operators described in
      the next three sections.  Note that the @ builtin command (q.v.) has
      its own separate syntax.

    Logical, arithmetical and comparison operators
      These operators are similar to those of C and have the same
      precedence.  They include

          ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
          <  > <<  >>  +  -  *  /  %  !  ~  (  )

      Here the precedence increases to the right, `==' `!=' `=~' and `!~',
      `<=' `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%'
      being, in groups, at the same level.  The `==' `!=' `=~' and `!~'
      operators compare their arguments as strings; all others operate on
      numbers.  The operators `=~' and `!~' are like `!=' and `==' except
      that the right hand side is a glob-pattern (see Filename substitution)
      against which the left hand operand is matched.  This reduces the need
      for use of the switch builtin command in shell scripts when all that
      is really needed is pattern matching.

      Null or missing arguments are considered `0'.  The results of all
      expressions are strings, which represent decimal numbers.  It is
      important to note that no two components of an expression can appear
      in the same word; except when adjacent to components of expressions
      which are syntactically significant to the parser (`&' `|' `<' `>' `('
      `)') they should be surrounded by spaces.

    Command exit status
      Commands can be executed in expressions and their exit status returned



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      by enclosing them in braces (`{}').  Remember that the braces should
      be separated from the words of the command by spaces.  Command
      executions succeed, returning true, i.e., `1', if the command exits
      with status 0, otherwise they fail, returning false, i.e., `0'.  If
      more detailed status information is required then the command should
      be executed outside of an expression and the status shell variable
      examined.

    File inquiry operators
      Some of these operators perform true/false tests on files and related
      objects.  They are of the form -op file, where op is one of

          r   Read access
          w   Write access
          x   Execute access
          X   Executable in the path or shell builtin, e.g., `-X ls' and `-X
              ls-F' are generally true, but `-X /bin/ls' is not (+)
          e   Existence
          o   Ownership
          z   Zero size
          s   Non-zero size (+)
          f   Plain file
          d   Directory
          l   Symbolic link (+) *
          b   Block special file (+)
          c   Character special file (+)
          p   Named pipe (fifo) (+) *
          S   Socket special file (+) *
          u   Set-user-ID bit is set (+)
          g   Set-group-ID bit is set (+)
          k   Sticky bit is set (+)
          t   file (which must be a digit) is an open file descriptor for a
              terminal device (+)
          R   Has been migrated (Convex only) (+)
          L   Applies subsequent operators in a multiple-operator test to a
              symbolic link rather than to the file to which the link points
              (+) *

      file is command and filename expanded and then tested to see if it has
      the specified relationship to the real user.  If file does not exist
      or is inaccessible or, for the operators indicated by `*', if the
      specified file type does not exist on the current system, then all
      inquiries return false, i.e., `0'.

      These operators may be combined for conciseness: `-xy file' is
      equivalent to `-x file && -y file'.  (+) For example, `-fx' is true
      (returns `1') for plain executable files, but not for directories.

      L may be used in a multiple-operator test to apply subsequent
      operators to a symbolic link rather than to the file to which the link
      points.  For example, `-lLo' is true for links owned by the invoking



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      user.  Lr, Lw and Lx are always true for links and false for non-
      links.  L has a different meaning when it is the last operator in a
      multiple-operator test; see below.

      It is possible but not useful, and sometimes misleading, to combine
      operators which expect file to be a file with operators which do not
      (e.g., X and t).  Following L with a non-file operator can lead to
      particularly strange results.

      Other operators return other information, i.e., not just `0' or `1'.
      (+) They have the same format as before; op may be one of

          A       Last file access time, as the number of seconds since the
                  epoch
          A:      Like A, but in timestamp format, e.g., `Fri May 14
                  16:36:10 1993'
          M       Last file modification time
          M:      Like M, but in timestamp format
          C       Last inode modification time
          C:      Like C, but in timestamp format
          D       Device number
          I       Inode number
          F       Composite file identifier, in the form device:inode
          L       The name of the file pointed to by a symbolic link
          N       Number of (hard) links
          P       Permissions, in octal, without leading zero
          P:      Like P, with leading zero
          Pmode   Equivalent to `-P file & mode', e.g., `-P22 file' returns
                  `22' if file is writable by group and other, `20' if by
                  group only, and `0' if by neither
          Pmode:  Like Pmode, with leading zero
          U       Numeric userid
          U:      Username, or the numeric userid if the username is unknown
          G       Numeric groupid
          G:      Groupname, or the numeric groupid if the groupname is
                  unknown
          Z       Size, in bytes

      Only one of these operators may appear in a multiple-operator test,
      and it must be the last.  Note that L has a different meaning at the
      end of and elsewhere in a multiple-operator test.  Because `0' is a
      valid return value for many of these operators, they do not return `0'
      when they fail: most return `-1', and F returns `:'.

      If the shell is compiled with POSIX defined (see the version shell
      variable), the result of a file inquiry is based on the permission
      bits of the file and not on the result of the access(2) system call.
      For example, if one tests a file with -w whose permissions would
      ordinarily allow writing but which is on a file system mounted read-
      only, the test will succeed in a POSIX shell but fail in a non-POSIX
      shell.



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      File inquiry operators can also be evaluated with the filetest builtin
      command (q.v.) (+).

    Jobs
      The shell associates a job with each pipeline.  It keeps a table of
      current jobs, printed by the jobs command, and assigns them small
      integer numbers.  When a job is started asynchronously with `&', the
      shell prints a line which looks like

          [1] 1234

      indicating that the job which was started asynchronously was job
      number 1 and had one (top-level) process, whose process id was 1234.

      If you are running a job and wish to do something else you may hit the
      suspend key (usually `^Z'), which sends a STOP signal to the current
      job.  The shell will then normally indicate that the job has been
      `Suspended' and print another prompt.  If the listjobs shell variable
      is set, all jobs will be listed like the jobs builtin command; if it
      is set to `long' the listing will be in long format, like `jobs -l'.
      You can then manipulate the state of the suspended job.  You can put
      it in the ``background'' with the bg command or run some other
      commands and eventually bring the job back into the ``foreground''
      with fg.  (See also the run-fg-editor editor command.) A `^Z' takes
      effect immediately and is like an interrupt in that pending output and
      unread input are discarded when it is typed.  The wait builtin command
      causes the shell to wait for all background jobs to complete.

      The `^]' key sends a delayed suspend signal, which does not generate a
      STOP signal until a program attempts to read(2) it, to the current
      job.  This can usefully be typed ahead when you have prepared some
      commands for a job which you wish to stop after it has read them.  The
      `^Y' key performs this function in csh(1); in tcsh, `^Y' is an editing
      command.  (+)

      A job being run in the background stops if it tries to read from the
      terminal.  Background jobs are normally allowed to produce output, but
      this can be disabled by giving the command `stty tostop'.  If you set
      this tty option, then background jobs will stop when they try to
      produce output like they do when they try to read input.

      There are several ways to refer to jobs in the shell.  The character
      `%' introduces a job name.  If you wish to refer to job number 1, you
      can name it as `%1'.  Just naming a job brings it to the foreground;
      thus `%1' is a synonym for `fg %1', bringing job 1 back into the
      foreground.  Similarly, saying `%1 &' resumes job 1 in the background,
      just like `bg %1'.  A job can also be named by an unambiguous prefix
      of the string typed in to start it: `%ex' would normally restart a
      suspended ex(1) job, if there were only one suspended job whose name
      began with the string `ex'.  It is also possible to say `%?string' to
      specify a job whose text contains string, if there is only one such



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      job.

      The shell maintains a notion of the current and previous jobs.  In
      output pertaining to jobs, the current job is marked with a `+' and
      the previous job with a `-'.  The abbreviations `%+', `%', and (by
      analogy with the syntax of the history mechanism) `%%' all refer to
      the current job, and `%-' refers to the previous job.

      The job control mechanism requires that the stty(1) option `new' be
      set on some systems.  It is an artifact from a `new' implementation of
      the tty driver which allows generation of interrupt characters from
      the keyboard to tell jobs to stop.  See stty(1) and the setty builtin
      command for details on setting options in the new tty driver.

    Status reporting
      The shell learns immediately whenever a process changes state.  It
      normally informs you whenever a job becomes blocked so that no further
      progress is possible, but only right before it prints a prompt.  This
      is done so that it does not otherwise disturb your work.  If, however,
      you set the shell variable notify, the shell will notify you
      immediately of changes of status in background jobs.  There is also a
      shell command notify which marks a single process so that its status
      changes will be immediately reported.  By default notify marks the
      current process; simply say `notify' after starting a background job
      to mark it.

      When you try to leave the shell while jobs are stopped, you will be
      warned that `There are suspended jobs.' You may use the jobs command
      to see what they are.  If you do this or immediately try to exit
      again, the shell will not warn you a second time, and the suspended
      jobs will be terminated.

    Automatic, periodic and timed events (+)
      There are various ways to run commands and take other actions
      automatically at various times in the ``life cycle'' of the shell.
      They are summarized here, and described in detail under the
      appropriate Builtin commands, Special shell variables and Special
      aliases.

      The sched builtin command puts commands in a scheduled-event list, to
      be executed by the shell at a given time.

      The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
      aliases can be set, respectively, to execute commands when the shell
      wants to ring the bell, when the working directory changes, every
      tperiod minutes, before each prompt, before each command gets
      executed, after each command gets executed, and when a job is started
      or is brought into the foreground.

      The autologout shell variable can be set to log out or lock the shell
      after a given number of minutes of inactivity.



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      The mail shell variable can be set to check for new mail periodically.

      The printexitvalue shell variable can be set to print the exit status
      of commands which exit with a status other than zero.

      The rmstar shell variable can be set to ask the user, when `rm *' is
      typed, if that is really what was meant.

      The time shell variable can be set to execute the time builtin command
      after the completion of any process that takes more than a given
      number of CPU seconds.

      The watch and who shell variables can be set to report when selected
      users log in or out, and the log builtin command reports on those
      users at any time.

    Native Language System support (+)
      The shell is eight bit clean (if so compiled; see the version shell
      variable) and thus supports character sets needing this capability.
      NLS support differs depending on whether or not the shell was compiled
      to use the system's NLS (again, see version).  In either case, 7-bit
      ASCII is the default character code (e.g., the classification of which
      characters are printable) and sorting, and changing the LANG or
      LC_CTYPE environment variables causes a check for possible changes in
      these respects.

      When using the system's NLS, the setlocale(3) function is called to
      determine appropriate character code/classification and sorting (e.g.,
      a 'en_CA.UTF-8' would yield "UTF-8" as a character code).  This
      function typically examines the LANG and LC_CTYPE environment
      variables; refer to the system documentation for further details.
      When not using the system's NLS, the shell simulates it by assuming
      that the ISO 8859-1 character set is used whenever either of the LANG
      and LC_CTYPE variables are set, regardless of their values.  Sorting
      is not affected for the simulated NLS.

      In addition, with both real and simulated NLS, all printable
      characters in the range \200-\377, i.e., those that have M-char
      bindings, are automatically rebound to self-insert-command.  The
      corresponding binding for the escape-char sequence, if any, is left
      alone.  These characters are not rebound if the NOREBIND environment
      variable is set.  This may be useful for the simulated NLS or a
      primitive real NLS which assumes full ISO 8859-1.  Otherwise, all M-
      char bindings in the range \240-\377 are effectively undone.
      Explicitly rebinding the relevant keys with bindkey is of course still
      possible.

      Unknown characters (i.e., those that are neither printable nor control
      characters) are printed in the format \nnn.  If the tty is not in 8
      bit mode, other 8 bit characters are printed by converting them to
      ASCII and using standout mode.  The shell never changes the 7/8 bit



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      mode of the tty and tracks user-initiated changes of 7/8 bit mode.
      NLS users (or, for that matter, those who want to use a meta key) may
      need to explicitly set the tty in 8 bit mode through the appropriate
      stty(1) command in, e.g., the ~/.login file.

    OS variant support (+)
      A number of new builtin commands are provided to support features in
      particular operating systems.  All are described in detail in the
      Builtin commands section.

      On systems that support TCF (aix-ibm370, aix-ps2), getspath and
      setspath get and set the system execution path, getxvers and setxvers
      get and set the experimental version prefix and migrate migrates
      processes between sites.  The jobs builtin prints the site on which
      each job is executing.

      Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
      operating system.

      Under Domain/OS, inlib adds shared libraries to the current
      environment, rootnode changes the rootnode and ver changes the
      systype.

      Under Mach, setpath is equivalent to Mach's setpath(1).

      Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

      Under Harris CX/UX, ucb or att runs a command under the specified
      universe.

      Under Convex/OS, warp prints or sets the universe.

      The VENDOR, OSTYPE and MACHTYPE environment variables indicate
      respectively the vendor, operating system and machine type
      (microprocessor class or machine model) of the system on which the
      shell thinks it is running.  These are particularly useful when
      sharing one's home directory between several types of machines; one
      can, for example,

          set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

      in one's ~/.login and put executables compiled for each machine in the
      appropriate directory.

      The version shell variable indicates what options were chosen when the
      shell was compiled.

      Note also the newgrp builtin, the afsuser and echo_style shell
      variables and the system-dependent locations of the shell's input
      files (see FILES).




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    Signal handling
      Login shells ignore interrupts when reading the file ~/.logout.  The
      shell ignores quit signals unless started with -q.  Login shells catch
      the terminate signal, but non-login shells inherit the terminate
      behavior from their parents.  Other signals have the values which the
      shell inherited from its parent.

      In shell scripts, the shell's handling of interrupt and terminate
      signals can be controlled with onintr, and its handling of hangups can
      be controlled with hup and nohup.

      The shell exits on a hangup (see also the logout shell variable).  By
      default, the shell's children do too, but the shell does not send them
      a hangup when it exits.  hup arranges for the shell to send a hangup
      to a child when it exits, and nohup sets a child to ignore hangups.

    Terminal management (+)
      The shell uses three different sets of terminal (``tty'') modes:
      `edit', used when editing, `quote', used when quoting literal
      characters, and `execute', used when executing commands.  The shell
      holds some settings in each mode constant, so commands which leave the
      tty in a confused state do not interfere with the shell.  The shell
      also matches changes in the speed and padding of the tty.  The list of
      tty modes that are kept constant can be examined and modified with the
      setty builtin.  Note that although the editor uses CBREAK mode (or its
      equivalent), it takes typed-ahead characters anyway.

      The echotc, settc and telltc commands can be used to manipulate and
      debug terminal capabilities from the command line.

      On systems that support SIGWINCH or SIGWINDOW, the shell adapts to
      window resizing automatically and adjusts the environment variables
      LINES and COLUMNS if set.  If the environment variable TERMCAP
      contains li# and co# fields, the shell adjusts them to reflect the new
      window size.

 REFERENCE
      The next sections of this manual describe all of the available Builtin
      commands, Special aliases and Special shell variables.

    Builtin commands
      %job    A synonym for the fg builtin command.

      %job &  A synonym for the bg builtin command.

      :       Does nothing, successfully.

      @
      @ name = expr
      @ name[index] = expr
      @ name++|--



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      @ name[index]++|--
              The first form prints the values of all shell variables.

              The second form assigns the value of expr to name.  The third
              form assigns the value of expr to the index'th component of
              name; both name and its index'th component must already exist.

              expr may contain the operators `*', `+', etc., as in C.  If
              expr contains `<', `>', `&' or `' then at least that part of
              expr must be placed within `()'.  Note that the syntax of expr
              has nothing to do with that described under Expressions.

              The fourth and fifth forms increment (`++') or decrement
              (`--') name or its index'th component.

              The space between `@' and name is required.  The spaces
              between name and `=' and between `=' and expr are optional.
              Components of expr must be separated by spaces.

      alias [name [wordlist]]
              Without arguments, prints all aliases.  With name, prints the
              alias for name.  With name and wordlist, assigns wordlist as
              the alias of name.  wordlist is command and filename
              substituted.  name may not be `alias' or `unalias'.  See also
              the unalias builtin command.

      alloc   Shows the amount of dynamic memory acquired, broken down into
              used and free memory.  With an argument shows the number of
              free and used blocks in each size category.  The categories
              start at size 8 and double at each step.  This command's
              output may vary across system types, because systems other
              than the VAX may use a different memory allocator.

      bg [%job ...]
              Puts the specified jobs (or, without arguments, the current
              job) into the background, continuing each if it is stopped.
              job may be a number, a string, `', `%', `+' or `-' as
              described under Jobs.

      bindkey [-l|-d|-e|-v|-u] (+)
      bindkey [-a] [-b] [-k] [-r] [--] key (+)
      bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
              Without options, the first form lists all bound keys and the
              editor command to which each is bound, the second form lists
              the editor command to which key is bound and the third form
              binds the editor command command to key.  Options include:

              -l  Lists all editor commands and a short description of each.
              -d  Binds all keys to the standard bindings for the default
                  editor, as per -e and -v below.




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              -e  Binds all keys to emacs(1)-style bindings.  Unsets vimode.
              -v  Binds all keys to vi(1)-style bindings.  Sets vimode.
              -a  Lists or changes key-bindings in the alternative key map.
                  This is the key map used in vimode command mode.
              -b  key is interpreted as a control character written
                  ^character (e.g., `^A') or C-character (e.g., `C-A'), a
                  meta character written M-character (e.g., `M-A'), a
                  function key written F-string (e.g., `F-string'), or an
                  extended prefix key written X-character (e.g., `X-A').
              -k  key is interpreted as a symbolic arrow key name, which may
                  be one of `down', `up', `left' or `right'.
              -r  Removes key's binding.  Be careful: `bindkey -r' does not
                  bind key to self-insert-command (q.v.), it unbinds key
                  completely.
              -c  command is interpreted as a builtin or external command
                  instead of an editor command.
              -s  command is taken as a literal string and treated as
                  terminal input when key is typed.  Bound keys in command
                  are themselves reinterpreted, and this continues for ten
                  levels of interpretation.
              --  Forces a break from option processing, so the next word is
                  taken as key even if it begins with '-'.
              -u (or any invalid option)
                  Prints a usage message.

              key may be a single character or a string.  If a command is
              bound to a string, the first character of the string is bound
              to sequence-lead-in and the entire string is bound to the
              command.

              Control characters in key can be literal (they can be typed by
              preceding them with the editor command quoted-insert, normally
              bound to `^V') or written caret-character style, e.g., `^A'.
              Delete is written `^?' (caret-question mark).  key and command
              can contain backslashed escape sequences (in the style of
              System V echo(1)) as follows:

                  \a      Bell
                  \b      Backspace
                  \e      Escape
                  \f      Form feed
                  \n      Newline
                  \r      Carriage return
                  \t      Horizontal tab
                  \v      Vertical tab
                  \nnn    The ASCII character corresponding to the octal
                          number nnn

              `\' nullifies the special meaning of the following character,
              if it has any, notably `\' and `^'.




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      bs2cmd bs2000-command (+)
              Passes bs2000-command to the BS2000 command interpreter for
              execution. Only non-interactive commands can be executed, and
              it is not possible to execute any command that would overlay
              the image of the current process, like /EXECUTE or /CALL-
              PROCEDURE. (BS2000 only)

      break   Causes execution to resume after the end of the nearest
              enclosing foreach or while.  The remaining commands on the
              current line are executed.  Multi-level breaks are thus
              possible by writing them all on one line.

      breaksw Causes a break from a switch, resuming after the endsw.

      builtins (+)
              Prints the names of all builtin commands.

      bye (+) A synonym for the logout builtin command.  Available only if
              the shell was so compiled; see the version shell variable.

      case label:
              A label in a switch statement as discussed below.

      cd [-p] [-l] [-n|-v] [I--] [name]
              If a directory name is given, changes the shell's working
              directory to name.  If not, changes to home, unless the
              cdtohome variable is not set, in which case a name is
              required.  If name is `-' it is interpreted as the previous
              working directory (see Other substitutions).  (+) If name is
              not a subdirectory of the current directory (and does not
              begin with `/', `./' or `../'), each component of the variable
              cdpath is checked to see if it has a subdirectory name.
              Finally, if all else fails but name is a shell variable whose
              value begins with `/' or '.', then this is tried to see if it
              is a directory, and the -p option is implied.

              With -p, prints the final directory stack, just like dirs.
              The -l, -n and -v flags have the same effect on cd as on dirs,
              and they imply -p.  (+) Using -- forces a break from option
              processing so the next word is taken as the directory name
              even if it begins with '-'. (+)

              See also the implicitcd and cdtohome shell variables.

      chdir   A synonym for the cd builtin command.

      complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
              Without arguments, lists all completions.  With command, lists
              completions for command.  With command and word etc., defines
              completions.




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              command may be a full command name or a glob-pattern (see
              Filename substitution).  It can begin with `-' to indicate
              that completion should be used only when command is ambiguous.

              word specifies which word relative to the current word is to
              be completed, and may be one of the following:

                  c   Current-word completion.  pattern is a glob-pattern
                      which must match the beginning of the current word on
                      the command line.  pattern is ignored when completing
                      the current word.
                  C   Like c, but includes pattern when completing the
                      current word.
                  n   Next-word completion.  pattern is a glob-pattern which
                      must match the beginning of the previous word on the
                      command line.
                  N   Like n, but must match the beginning of the word two
                      before the current word.
                  p   Position-dependent completion.  pattern is a numeric
                      range, with the same syntax used to index shell
                      variables, which must include the current word.

              list, the list of possible completions, may be one of the
              following:

                  a       Aliases
                  b       Bindings (editor commands)
                  c       Commands (builtin or external commands)
                  C       External commands which begin with the supplied
                          path prefix
                  d       Directories
                  D       Directories which begin with the supplied path
                          prefix
                  e       Environment variables
                  f       Filenames
                  F       Filenames which begin with the supplied path
                          prefix
                  g       Groupnames
                  j       Jobs
                  l       Limits
                  n       Nothing
                  s       Shell variables
                  S       Signals
                  t       Plain (``text'') files
                  T       Plain (``text'') files which begin with the
                          supplied path prefix
                  v       Any variables
                  u       Usernames
                  x       Like n, but prints select when list-choices is
                          used.




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                  X       Completions
                  $var    Words from the variable var
                  (...)   Words from the given list
                  `...`   Words from the output of command

              select is an optional glob-pattern.  If given, words from only
              list that match select are considered and the fignore shell
              variable is ignored.  The last three types of completion may
              not have a select pattern, and x uses select as an explanatory
              message when the list-choices editor command is used.

              suffix is a single character to be appended to a successful
              completion.  If null, no character is appended.  If omitted
              (in which case the fourth delimiter can also be omitted), a
              slash is appended to directories and a space to other words.

              command invoked from `...` version has additional environment
              variable set, the variable name is COMMAND_LINE and contains
              (as its name indicates) contents of the current (already typed
              in) command line. One can examine and use contents of the
              COMMAND_LINE variable in her custom script to build more
              sophisticated completions (see completion for svn(1) included
              in this package).

              Now for some examples.  Some commands take only directories as
              arguments, so there's no point completing plain files.

                  > complete cd 'p/1/d/'

              completes only the first word following `cd' (`p/1') with a
              directory.  p-type completion can also be used to narrow down
              command completion:

                  > co[^D]
                  complete compress
                  > complete -co* 'p/0/(compress)/'
                  > co[^D]
                  > compress

              This completion completes commands (words in position 0,
              `p/0') which begin with `co' (thus matching `co*') to
              `compress' (the only word in the list).  The leading `-'
              indicates that this completion is to be used with only
              ambiguous commands.

                  > complete find 'n/-user/u/'

              is an example of n-type completion.  Any word following `find'
              and immediately following `-user' is completed from the list
              of users.




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                  > complete cc 'c/-I/d/'

              demonstrates c-type completion.  Any word following `cc' and
              beginning with `-I' is completed as a directory.  `-I' is not
              taken as part of the directory because we used lowercase c.

              Different lists are useful with different commands.

                  > complete alias 'p/1/a/'
                  > complete man 'p/*/c/'
                  > complete set 'p/1/s/'
                  > complete true 'p/1/x:Truth has no options./'

              These complete words following `alias' with aliases, `man'
              with commands, and `set' with shell variables.  `true' doesn't
              have any options, so x does nothing when completion is
              attempted and prints `Truth has no options.' when completion
              choices are listed.

              Note that the man example, and several other examples below,
              could just as well have used 'c/*' or 'n/*' as 'p/*'.

              Words can be completed from a variable evaluated at completion
              time,

                  > complete ftp 'p/1/$hostnames/'
                  > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                  > ftp [^D]
                  rtfm.mit.edu tesla.ee.cornell.edu
                  > ftp [^C]
                  > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
                  uunet.uu.net)
                  > ftp [^D]
                  rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

              or from a command run at completion time:

                  > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                  > kill -9 [^D]
                  23113 23377 23380 23406 23429 23529 23530 PID

              Note that the complete command does not itself quote its
              arguments, so the braces, space and `$' in `{print $1}' must
              be quoted explicitly.

              One command can have multiple completions:

                  > complete dbx 'p/2/(core)/' 'p/*/c/'

              completes the second argument to `dbx' with the word `core'
              and all other arguments with commands.  Note that the



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              positional completion is specified before the next-word
              completion.  Because completions are evaluated from left to
              right, if the next-word completion were specified first it
              would always match and the positional completion would never
              be executed.  This is a common mistake when defining a
              completion.

              The select pattern is useful when a command takes files with
              only particular forms as arguments.  For example,

                  > complete cc 'p/*/f:*.[cao]/'

              completes `cc' arguments to files ending in only `.c', `.a',
              or `.o'.  select can also exclude files, using negation of a
              glob-pattern as described under Filename substitution.  One
              might use

                  > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

              to exclude precious source code from `rm' completion.  Of
              course, one could still type excluded names manually or
              override the completion mechanism using the complete-word-raw
              or list-choices-raw editor commands (q.v.).

              The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
              respectively, but they use the select argument in a different
              way: to restrict completion to files beginning with a
              particular path prefix.  For example, the Elm mail program
              uses `=' as an abbreviation for one's mail directory.  One
              might use

                  > complete elm c@=@F:$HOME/Mail/@

              to complete `elm -f =' as if it were `elm -f ~/Mail/'.  Note
              that we used `@' instead of `/' to avoid confusion with the
              select argument, and we used `$HOME' instead of `~' because
              home directory substitution works at only the beginning of a
              word.

              suffix is used to add a nonstandard suffix (not space or `/'
              for directories) to completed words.

                  > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

              completes arguments to `finger' from the list of users,
              appends an `@', and then completes after the `@' from the
              `hostnames' variable.  Note again the order in which the
              completions are specified.

              Finally, here's a complex example for inspiration:




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                  > complete find \
                  'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                  'n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                  'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                  'n/-type/(b c d f l p s)/' \
                  'c/-/(name newer cpio ncpio exec ok user \
                  group fstype type atime ctime depth inum \
                  ls mtime nogroup nouser perm print prune \
                  size xdev)/' \
                  'p/*/d/'

              This completes words following `-name', `-newer', `-cpio' or
              `ncpio' (note the pattern which matches both) to files, words
              following `-exec' or `-ok' to commands, words following `user'
              and `group' to users and groups respectively and words
              following `-fstype' or `-type' to members of the given lists.
              It also completes the switches themselves from the given list
              (note the use of c-type completion) and completes anything not
              otherwise completed to a directory.  Whew.

              Remember that programmed completions are ignored if the word
              being completed is a tilde substitution (beginning with `~')
              or a variable (beginning with `$').  See also the uncomplete
              builtin command.

      continue
              Continues execution of the nearest enclosing while or foreach.
              The rest of the commands on the current line are executed.

      default:
              Labels the default case in a switch statement.  It should come
              after all case labels.

      dirs [-l] [-n|-v]
      dirs -S|-L [filename] (+)
      dirs -c (+)
              The first form prints the directory stack.  The top of the
              stack is at the left and the first directory in the stack is
              the current directory.  With -l, `~' or `~name' in the output
              is expanded explicitly to home or the pathname of the home
              directory for user name.  (+) With -n, entries are wrapped
              before they reach the edge of the screen.  (+) With -v,
              entries are printed one per line, preceded by their stack
              positions.  (+) If more than one of -n or -v is given, -v
              takes precedence.  -p is accepted but does nothing.

              With -S, the second form saves the directory stack to filename
              as a series of cd and pushd commands.  With -L, the shell
              sources filename, which is presumably a directory stack file
              saved by the -S option or the savedirs mechanism.  In either
              case, dirsfile is used if filename is not given and ~/.cshdirs



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              is used if dirsfile is unset.

              Note that login shells do the equivalent of `dirs -L' on
              startup and, if savedirs is set, `dirs -S' before exiting.
              Because only ~/.tcshrc is normally sourced before ~/.cshdirs,
              dirsfile should be set in ~/.tcshrc rather than ~/.login.

              The last form clears the directory stack.

      echo [-n] word ...
              Writes each word to the shell's standard output, separated by
              spaces and terminated with a newline.  The echo_style shell
              variable may be set to emulate (or not) the flags and escape
              sequences of the BSD and/or System V versions of echo; see
              echo(1).

      echotc [-sv] arg ... (+)
              Exercises the terminal capabilities (see termcap(5)) in args.
              For example, 'echotc home' sends the cursor to the home
              position, 'echotc cm 3 10' sends it to column 3 and row 10,
              and 'echotc ts 0; echo "This is a test."; echotc fs' prints
              "This is a test." in the status line.

              If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints
              the value of that capability ("yes" or "no" indicating that
              the terminal does or does not have that capability).  One
              might use this to make the output from a shell script less
              verbose on slow terminals, or limit command output to the
              number of lines on the screen:

                  > set history=`echotc lines`
                  > @ history--

              Termcap strings may contain wildcards which will not echo
              correctly.  One should use double quotes when setting a shell
              variable to a terminal capability string, as in the following
              example that places the date in the status line:

                  > set tosl="`echotc ts 0`"
                  > set frsl="`echotc fs`"
                  > echo -n "$tosl";date; echo -n "$frsl"

              With -s, nonexistent capabilities return the empty string
              rather than causing an error.  With -v, messages are verbose.

      else
      end
      endif
      endsw   See the description of the foreach, if, switch, and while
              statements below.




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      eval arg ...
              Treats the arguments as input to the shell and executes the
              resulting command(s) in the context of the current shell.
              This is usually used to execute commands generated as the
              result of command or variable substitution, because parsing
              occurs before these substitutions.  See tset(1) for a sample
              use of eval.

      exec command
              Executes the specified command in place of the current shell.

      exit [expr]
              The shell exits either with the value of the specified expr
              (an expression, as described under Expressions) or, without
              expr, with the value 0.

      fg [%job ...]
              Brings the specified jobs (or, without arguments, the current
              job) into the foreground, continuing each if it is stopped.
              job may be a number, a string, `', `%', `+' or `-' as
              described under Jobs.  See also the run-fg-editor editor
              command.

      filetest -op file ... (+)
              Applies op (which is a file inquiry operator as described
              under File inquiry operators) to each file and returns the
              results as a space-separated list.

      foreach name (wordlist)
      ...
      end     Successively sets the variable name to each member of wordlist
              and executes the sequence of commands between this command and
              the matching end.  (Both foreach and end must appear alone on
              separate lines.)  The builtin command continue may be used to
              continue the loop prematurely and the builtin command break to
              terminate it prematurely.  When this command is read from the
              terminal, the loop is read once prompting with `foreach? ' (or
              prompt2) before any statements in the loop are executed.  If
              you make a mistake typing in a loop at the terminal you can
              rub it out.

      getspath (+)
              Prints the system execution path.  (TCF only)

      getxvers (+)
              Prints the experimental version prefix.  (TCF only)

      glob wordlist
              Like echo, but the `-n' parameter is not recognized and words
              are delimited by null characters in the output.  Useful for
              programs which wish to use the shell to filename expand a list



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              of words.

      goto word
              word is filename and command-substituted to yield a string of
              the form `label'.  The shell rewinds its input as much as
              possible, searches for a line of the form `label:', possibly
              preceded by blanks or tabs, and continues execution after that
              line.

      hashstat
              Prints a statistics line indicating how effective the internal
              hash table has been at locating commands (and avoiding
              exec's).  An exec is attempted for each component of the path
              where the hash function indicates a possible hit, and in each
              component which does not begin with a `/'.

              On machines without vfork(2), prints only the number and size
              of hash buckets.

      history [-hTr] [n]
      history -S|-L|-M [filename] (+)
      history -c (+)
              The first form prints the history event list.  If n is given
              only the n most recent events are printed or saved.  With -h,
              the history list is printed without leading numbers.  If -T is
              specified, timestamps are printed also in comment form.  (This
              can be used to produce files suitable for loading with
              'history -L' or 'source -h'.) With -r, the order of printing
              is most recent first rather than oldest first.

              With -S, the second form saves the history list to filename.
              If the first word of the savehist shell variable is set to a
              number, at most that many lines are saved.  If the second word
              of savehist is set to `merge', the history list is merged with
              the existing history file instead of replacing it (if there is
              one) and sorted by time stamp.  (+) Merging is intended for an
              environment like the X Window System with several shells in
              simultaneous use.  If the second word of savehist is `merge'
              and the third word is set to `lock', the history file update
              will be serialized with other shell sessions that would
              possibly like to merge history at exactly the same time.

              With -L, the shell appends filename, which is presumably a
              history list saved by the -S option or the savehist mechanism,
              to the history list.  -M is like -L, but the contents of
              filename are merged into the history list and sorted by
              timestamp.  In either case, histfile is used if filename is
              not given and ~/.history is used if histfile is unset.
              `history -L' is exactly like 'source -h' except that it does
              not require a filename.




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              Note that login shells do the equivalent of `history -L' on
              startup and, if savehist is set, `history -S' before exiting.
              Because only ~/.tcshrc is normally sourced before ~/.history,
              histfile should be set in ~/.tcshrc rather than ~/.login.

              If histlit is set, the first and second forms print and save
              the literal (unexpanded) form of the history list.

              The last form clears the history list.

      hup [command] (+)
              With command, runs command such that it will exit on a hangup
              signal and arranges for the shell to send it a hangup signal
              when the shell exits.  Note that commands may set their own
              response to hangups, overriding hup.  Without an argument,
              causes the non-interactive shell only to exit on a hangup for
              the remainder of the script.  See also Signal handling and the
              nohup builtin command.

      if (expr) command
              If expr (an expression, as described under Expressions)
              evaluates true, then command is executed.  Variable
              substitution on command happens early, at the same time it
              does for the rest of the if command.  command must be a simple
              command, not an alias, a pipeline, a command list or a
              parenthesized command list, but it may have arguments.
              Input/output redirection occurs even if expr is false and
              command is thus not executed; this is a bug.

      if (expr) then
      ...
      else if (expr2) then
      ...
      else
      ...
      endif   If the specified expr is true then the commands to the first
              else are executed; otherwise if expr2 is true then the
              commands to the second else are executed, etc.  Any number of
              else-if pairs are possible; only one endif is needed.  The
              else part is likewise optional.  (The words else and endif
              must appear at the beginning of input lines; the if must
              appear alone on its input line or after an else.)

      inlib shared-library ... (+)
              Adds each shared-library to the current environment.  There is
              no way to remove a shared library.  (Domain/OS only)

      jobs [-l]
              Lists the active jobs.  With -l, lists process IDs in addition
              to the normal information.  On TCF systems, prints the site on
              which each job is executing.



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      kill [-s signal] %job|pid ...
      kill -l The first and second forms sends the specified signal (or, if
              none is given, the TERM (terminate) signal) to the specified
              jobs or processes.  job may be a number, a string, `', `%',
              `+' or `-' as described under Jobs.  Signals are either given
              by number or by name (as given in /usr/include/signal.h,
              stripped of the prefix `SIG').  There is no default job;
              saying just `kill' does not send a signal to the current job.
              If the signal being sent is TERM (terminate) or HUP (hangup),
              then the job or process is sent a CONT (continue) signal as
              well.  The third form lists the signal names.

      limit [-h] [resource [maximum-use]]
              Limits the consumption by the current process and each process
              it creates to not individually exceed maximum-use on the
              specified resource.  If no maximum-use is given, then the
              current limit is printed; if no resource is given, then all
              limitations are given.  If the -h flag is given, the hard
              limits are used instead of the current limits.  The hard
              limits impose a ceiling on the values of the current limits.
              Only the super-user may raise the hard limits, but a user may
              lower or raise the current limits within the legal range.

              Controllable resources currently include (if supported by the
              OS):

              cputime
                   the maximum number of cpu-seconds to be used by each
                   process

              filesize
                   the largest single file which can be created

              datasize
                   the maximum growth of the data+stack region via sbrk(2)
                   beyond the end of the program text

              stacksize
                   the maximum size of the automatically-extended stack
                   region

              coredumpsize
                   the size of the largest core dump that will be created

              memoryuse
                   the maximum amount of physical memory a process may have
                   allocated to it at a given time

              vmemoryuse
                   the maximum amount of virtual memory a process may have
                   allocated to it at a given time (address space)



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              vmemoryuse
                   the maximum amount of virtual memory a process may have
                   allocated to it at a given time

              heapsize
                   the maximum amount of memory a process may allocate per
                   brk() system call

              descriptors or openfiles
                   the maximum number of open files for this process

              pseudoterminals
                   the maximum number of pseudo-terminals for this user

              kqueues
                   the maximum number of kqueues allocated for this process

              concurrency
                   the maximum number of threads for this process

              memorylocked
                   the maximum size which a process may lock into memory
                   using mlock(2)

              maxproc
                   the maximum number of simultaneous processes for this
                   user id

              maxthread
                   the maximum number of simultaneous threads (lightweight
                   processes) for this user id

              threads
                   the maximum number of threads for this process

              sbsize
                   the maximum size of socket buffer usage for this user

              swapsize
                   the maximum amount of swap space reserved or used for
                   this user

              maxlocks
                   the maximum number of locks for this user

              posixlocks
                   the maximum number of POSIX advisory locks for this user

              maxsignal
                   the maximum number of pending signals for this user




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              maxmessage
                   the maximum number of bytes in POSIX mqueues for this
                   user

              maxnice
                   the maximum nice priority the user is allowed to raise
                   mapped from [19...-20] to [0...39] for this user

              maxrtprio
                   the maximum realtime priority for this user maxrttime the
                   timeout for RT tasks in microseconds for this user.

              maximum-use may be given as a (floating point or integer)
              number followed by a scale factor.  For all limits other than
              cputime the default scale is `k' or `kilobytes' (1024 bytes);
              a scale factor of `m' or `megabytes' or `g' or `gigabytes' may
              also be used.  For cputime the default scaling is `seconds',
              while `m' for minutes or `h' for hours, or a time of the form
              `mm:ss' giving minutes and seconds may be used.

              If maximum-use  is `unlimited', then the limitation on the
              specified resource is removed (this is equivalent to the
              unlimit builtin command).

              For both resource names and scale factors, unambiguous
              prefixes of the names suffice.

      log (+) Prints the watch shell variable and reports on each user
              indicated in watch who is logged in, regardless of when they
              last logged in.  See also watchlog.

      login   Terminates a login shell, replacing it with an instance of
              /bin/login. This is one way to log off, included for
              compatibility with sh(1).

      logout  Terminates a login shell.  Especially useful if ignoreeof is
              set.

      ls-F [-switch ...] [file ...] (+)
              Lists files like `ls -F', but much faster.  It identifies each
              type of special file in the listing with a special character:

              /   Directory
              *   Executable
              #   Block device
              %   Character device
              |   Named pipe (systems with named pipes only)
              =   Socket (systems with sockets only)
              @   Symbolic link (systems with symbolic links only)
              +   Hidden directory (AIX only) or context dependent (HP/UX
                  only)



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              :   Network special (HP/UX only)

              If the listlinks shell variable is set, symbolic links are
              identified in more detail (on only systems that have them, of
              course):

              @   Symbolic link to a non-directory
              >   Symbolic link to a directory
              &   Symbolic link to nowhere

              listlinks also slows down ls-F and causes partitions holding
              files pointed to by symbolic links to be mounted.

              If the listflags shell variable is set to `x', `a' or `A', or
              any combination thereof (e.g., `xA'), they are used as flags
              to ls-F, making it act like `ls -xF', `ls -Fa', `ls -FA' or a
              combination (e.g., `ls -FxA').  On machines where `ls -C' is
              not the default, ls-F acts like `ls -CF', unless listflags
              contains an `x', in which case it acts like `ls -xF'.  ls-F
              passes its arguments to ls(1) if it is given any switches, so
              `alias ls ls-F' generally does the right thing.

              The ls-F builtin can list files using different colors
              depending on the filetype or extension.  See the color shell
              variable and the LS_COLORS environment variable.

      migrate [-site] pid|%jobid ... (+)
      migrate -site (+)
              The first form migrates the process or job to the site
              specified or the default site determined by the system path.
              The second form is equivalent to `migrate -site $$': it
              migrates the current process to the specified site.  Migrating
              the shell itself can cause unexpected behavior, because the
              shell does not like to lose its tty.  (TCF only)

      newgrp [-] [group] (+)
              Equivalent to `exec newgrp'; see newgrp(1).  Available only if
              the shell was so compiled; see the version shell variable.

      nice [+number] [command]
              Sets the scheduling priority for the shell to number, or,
              without number, to 4.  With command, runs command at the
              appropriate priority.  The greater the number, the less cpu
              the process gets.  The super-user may specify negative
              priority by using `nice -number ...'.  Command is always
              executed in a sub-shell, and the restrictions placed on
              commands in simple if statements apply.

      nohup [command]
              With command, runs command such that it will ignore hangup
              signals.  Note that commands may set their own response to



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              hangups, overriding nohup.  Without an argument, causes the
              non-interactive shell only to ignore hangups for the remainder
              of the script.  See also Signal handling and the hup builtin
              command.

      notify [%job ...]
              Causes the shell to notify the user asynchronously when the
              status of any of the specified jobs (or, without %job, the
              current job) changes, instead of waiting until the next prompt
              as is usual.  job may be a number, a string, `', `%', `+' or
              `-' as described under Jobs.  See also the notify shell
              variable.

      onintr [-|label]
              Controls the action of the shell on interrupts.  Without
              arguments, restores the default action of the shell on
              interrupts, which is to terminate shell scripts or to return
              to the terminal command input level.  With `-', causes all
              interrupts to be ignored.  With label, causes the shell to
              execute a `goto label' when an interrupt is received or a
              child process terminates because it was interrupted.

              onintr is ignored if the shell is running detached and in
              system startup files (see FILES), where interrupts are
              disabled anyway.

      popd [-p] [-l] [-n|-v] [+n]
              Without arguments, pops the directory stack and returns to the
              new top directory.  With a number `+n', discards the n'th
              entry in the stack.

              Finally, all forms of popd print the final directory stack,
              just like dirs.  The pushdsilent shell variable can be set to
              prevent this and the -p flag can be given to override
              pushdsilent.  The -l, -n and -v flags have the same effect on
              popd as on dirs.  (+)

      printenv [name] (+)
              Prints the names and values of all environment variables or,
              with name, the value of the environment variable name.

      pushd [-p] [-l] [-n|-v] [name|+n]
              Without arguments, exchanges the top two elements of the
              directory stack.  If pushdtohome is set, pushd without
              arguments does `pushd ~', like cd.  (+) With name, pushes the
              current working directory onto the directory stack and changes
              to name.  If name is `-' it is interpreted as the previous
              working directory (see Filename substitution).  (+) If dunique
              is set, pushd removes any instances of name from the stack
              before pushing it onto the stack.  (+) With a number `+n',
              rotates the nth element of the directory stack around to be



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                              24 November 2016



              the top element and changes to it.  If dextract is set,
              however, `pushd +n' extracts the nth directory, pushes it onto
              the top of the stack and changes to it.  (+)

              Finally, all forms of pushd print the final directory stack,
              just like dirs.  The pushdsilent shell variable can be set to
              prevent this and the -p flag can be given to override
              pushdsilent.  The -l, -n and -v flags have the same effect on
              pushd as on dirs.  (+)

      rehash  Causes the internal hash table of the contents of the
              directories in the path variable to be recomputed.  This is
              needed if the autorehash shell variable is not set and new
              commands are added to directories in path while you are logged
              in.  With autorehash, a new command will be found
              automatically, except in the special case where another
              command of the same name which is located in a different
              directory already exists in the hash table.  Also flushes the
              cache of home directories built by tilde expansion.

      repeat count command
              The specified command, which is subject to the same
              restrictions as the command in the one line if statement
              above, is executed count times.  I/O redirections occur
              exactly once, even if count is 0.

      rootnode //nodename (+)
              Changes the rootnode to //nodename, so that `/' will be
              interpreted as `//nodename'.  (Domain/OS only)

      sched (+)
      sched [+]hh:mm command (+)
      sched -n (+)
              The first form prints the scheduled-event list.  The sched
              shell variable may be set to define the format in which the
              scheduled-event list is printed.  The second form adds command
              to the scheduled-event list.  For example,

                  > sched 11:00 echo It\'s eleven o\'clock.

              causes the shell to echo `It's eleven o'clock.' at 11 AM.  The
              time may be in 12-hour AM/PM format

                  > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

              or may be relative to the current time:

                  > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

              A relative time specification may not use AM/PM format.  The
              third form removes item n from the event list:



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                  > sched
                       1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                       2  Wed Apr  4 17:00  set prompt=[%h] It's after 5; go
                  home: >
                  > sched -2
                  > sched
                       1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

              A command in the scheduled-event list is executed just before
              the first prompt is printed after the time when the command is
              scheduled.  It is possible to miss the exact time when the
              command is to be run, but an overdue command will execute at
              the next prompt.  A command which comes due while the shell is
              waiting for user input is executed immediately.  However,
              normal operation of an already-running command will not be
              interrupted so that a scheduled-event list element may be run.

              This mechanism is similar to, but not the same as, the at(1)
              command on some Unix systems.  Its major disadvantage is that
              it may not run a command at exactly the specified time.  Its
              major advantage is that because sched runs directly from the
              shell, it has access to shell variables and other structures.
              This provides a mechanism for changing one's working
              environment based on the time of day.

      set
      set name ...
      set name=word ...
      set [-r] [-f|-l] name=(wordlist) ... (+)
      set name[index]=word ...
      set -r (+)
      set -r name ... (+)
      set -r name=word ... (+)
              The first form of the command prints the value of all shell
              variables.  Variables which contain more than a single word
              print as a parenthesized word list.  The second form sets name
              to the null string.  The third form sets name to the single
              word.  The fourth form sets name to the list of words in
              wordlist.  In all cases the value is command and filename
              expanded.  If -r is specified, the value is set read-only.  If
              -f or -l are specified, set only unique words keeping their
              order.  -f prefers the first occurrence of a word, and -l the
              last.  The fifth form sets the index'th component of name to
              word; this component must already exist.  The sixth form lists
              only the names of all shell variables that are read-only.  The
              seventh form makes name read-only, whether or not it has a
              value.  The eighth form is the same as the third form, but
              make name read-only at the same time.

              These arguments can be repeated to set and/or make read-only
              multiple variables in a single set command.  Note, however,



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              that variable expansion happens for all arguments before any
              setting occurs.  Note also that `=' can be adjacent to both
              name and word or separated from both by whitespace, but cannot
              be adjacent to only one or the other.  See also the unset
              builtin command.

      setenv [name [value]]
              Without arguments, prints the names and values of all
              environment variables.  Given name, sets the environment
              variable name to value or, without value, to the null string.

      setpath path (+)
              Equivalent to setpath(1).  (Mach only)

      setspath LOCAL|site|cpu ... (+)
              Sets the system execution path.  (TCF only)

      settc cap value (+)
              Tells the shell to believe that the terminal capability cap
              (as defined in termcap(5)) has the value value.  No sanity
              checking is done.  Concept terminal users may have to `settc
              xn no' to get proper wrapping at the rightmost column.

      setty [-d|-q|-x] [-a] [[+|-]mode] (+)
              Controls which tty modes (see Terminal management) the shell
              does not allow to change.  -d, -q or -x tells setty to act on
              the `edit', `quote' or `execute' set of tty modes
              respectively; without -d, -q or -x, `execute' is used.

              Without other arguments, setty lists the modes in the chosen
              set which are fixed on (`+mode') or off (`-mode').  The
              available modes, and thus the display, vary from system to
              system.  With -a, lists all tty modes in the chosen set
              whether or not they are fixed.  With +mode, -mode or mode,
              fixes mode on or off or removes control from mode in the
              chosen set.  For example, `setty +echok echoe' fixes `echok'
              mode on and allows commands to turn `echoe' mode on or off,
              both when the shell is executing commands.

      setxvers [string] (+)
              Set the experimental version prefix to string, or removes it
              if string is omitted.  (TCF only)

      shift [variable]
              Without arguments, discards argv[1] and shifts the members of
              argv to the left.  It is an error for argv not to be set or to
              have less than one word as value.  With variable, performs the
              same function on variable.

      source [-h] name [args ...]
              The shell reads and executes commands from name.  The commands



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              are not placed on the history list.  If any args are given,
              they are placed in argv.  (+) source commands may be nested;
              if they are nested too deeply the shell may run out of file
              descriptors.  An error in a source at any level terminates all
              nested source commands.  With -h, commands are placed on the
              history list instead of being executed, much like `history
              -L'.

      stop %job|pid ...
              Stops the specified jobs or processes which are executing in
              the background.  job may be a number, a string, `', `%', `+'
              or `-' as described under Jobs.  There is no default job;
              saying just `stop' does not stop the current job.

      suspend Causes the shell to stop in its tracks, much as if it had been
              sent a stop signal with ^Z.  This is most often used to stop
              shells started by su(1).

      switch (string)
      case str1:
          ...
          breaksw
      ...
      default:
          ...
          breaksw
      endsw   Each case label is successively matched, against the specified
              string which is first command and filename expanded.  The file
              metacharacters `*', `?' and `[...]'  may be used in the case
              labels, which are variable expanded.  If none of the labels
              match before a `default' label is found, then the execution
              begins after the default label.  Each case label and the
              default label must appear at the beginning of a line.  The
              command breaksw causes execution to continue after the endsw.
              Otherwise control may fall through case labels and default
              labels as in C.  If no label matches and there is no default,
              execution continues after the endsw.

      telltc (+)
              Lists the values of all terminal capabilities (see
              termcap(5)).

      termname [terminal type] (+)
              Tests if terminal type (or the current value of TERM if no
              terminal type is given) has an entry in the hosts termcap(5)
              or terminfo(5) database. Prints the terminal type to stdout
              and returns 0 if an entry is present otherwise returns 1.

      time [command]
              Executes command (which must be a simple command, not an
              alias, a pipeline, a command list or a parenthesized command



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              list) and prints a time summary as described under the time
              variable.  If necessary, an extra shell is created to print
              the time statistic when the command completes.  Without
              command, prints a time summary for the current shell and its
              children.

      umask [value]
              Sets the file creation mask to value, which is given in octal.
              Common values for the mask are 002, giving all access to the
              group and read and execute access to others, and 022, giving
              read and execute access to the group and others.  Without
              value, prints the current file creation mask.

      unalias pattern
              Removes all aliases whose names match pattern.  `unalias *'
              thus removes all aliases.  It is not an error for nothing to
              be unaliased.

      uncomplete pattern (+)
              Removes all completions whose names match pattern.
              `uncomplete *' thus removes all completions.  It is not an
              error for nothing to be uncompleted.

      unhash  Disables use of the internal hash table to speed location of
              executed programs.

      universe universe (+)
              Sets the universe to universe.  (Masscomp/RTU only)

      unlimit [-hf] [resource]
              Removes the limitation on resource or, if no resource is
              specified, all resource limitations.  With -h, the
              corresponding hard limits are removed.  Only the super-user
              may do this.  Note that unlimit may not exit successful, since
              most systems do not allow descriptors to be unlimited.  With
              -f errors are ignored.

      unset pattern
              Removes all variables whose names match pattern, unless they
              are read-only.  `unset *' thus removes all variables unless
              they are read-only; this is a bad idea.  It is not an error
              for nothing to be unset.

      unsetenv pattern
              Removes all environment variables whose names match pattern.
              `unsetenv *' thus removes all environment variables; this is a
              bad idea.  It is not an error for nothing to be unsetenved.

      ver [systype [command]] (+)
              Without arguments, prints SYSTYPE.  With systype, sets SYSTYPE
              to systype.  With systype and command, executes command under



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              systype.  systype may be `bsd4.3' or `sys5.3'.  (Domain/OS
              only)

      wait    The shell waits for all background jobs.  If the shell is
              interactive, an interrupt will disrupt the wait and cause the
              shell to print the names and job numbers of all outstanding
              jobs.

      warp universe (+)
              Sets the universe to universe.  (Convex/OS only)

      watchlog (+)
              An alternate name for the log builtin command (q.v.).
              Available only if the shell was so compiled; see the version
              shell variable.

      where command (+)
              Reports all known instances of command, including aliases,
              builtins and executables in path.

      which command (+)
              Displays the command that will be executed by the shell after
              substitutions, path searching, etc.  The builtin command is
              just like which(1), but it correctly reports tcsh aliases and
              builtins and is 10 to 100 times faster.  See also the which-
              command editor command.

      while (expr)
      ...
      end     Executes the commands between the while and the matching end
              while expr (an expression, as described under Expressions)
              evaluates non-zero.  while and end must appear alone on their
              input lines.  break and continue may be used to terminate or
              continue the loop prematurely.  If the input is a terminal,
              the user is prompted the first time through the loop as with
              foreach.

    Special aliases (+)
      If set, each of these aliases executes automatically at the indicated
      time.  They are all initially undefined.

      beepcmd Runs when the shell wants to ring the terminal bell.

      cwdcmd  Runs after every change of working directory.  For example, if
              the user is working on an X window system using xterm(1) and a
              re-parenting window manager that supports title bars such as
              twm(1) and does

                  > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'





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              then the shell will change the title of the running xterm(1)
              to be the name of the host, a colon, and the full current
              working directory.  A fancier way to do that is

                  > alias cwdcmd 'echo -n
                  "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

              This will put the hostname and working directory on the title
              bar but only the hostname in the icon manager menu.

              Note that putting a cd, pushd or popd in cwdcmd may cause an
              infinite loop.  It is the author's opinion that anyone doing
              so will get what they deserve.

      jobcmd  Runs before each command gets executed, or when the command
              changes state.  This is similar to postcmd, but it does not
              print builtins.

                  > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

              then executing vi foo.c will put the command string in the
              xterm title bar.

      helpcommand
              Invoked by the run-help editor command.  The command name for
              which help is sought is passed as sole argument.  For example,
              if one does

                  > alias helpcommand '\!:1 --help'

              then the help display of the command itself will be invoked,
              using the GNU help calling convention.  Currently there is no
              easy way to account for various calling conventions (e.g., the
              customary Unix `-h'), except by using a table of many
              commands.

      periodic
              Runs every tperiod minutes.  This provides a convenient means
              for checking on common but infrequent changes such as new
              mail.  For example, if one does

                  > set tperiod = 30
                  > alias periodic checknews

              then the checknews(1) program runs every 30 minutes.  If
              periodic is set but tperiod is unset or set to 0, periodic
              behaves like precmd.

      precmd  Runs just before each prompt is printed.  For example, if one
              does




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                  > alias precmd date

              then date(1) runs just before the shell prompts for each
              command.  There are no limits on what precmd can be set to do,
              but discretion should be used.

      postcmd Runs before each command gets executed.

                  > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

              then executing vi foo.c will put the command string in the
              xterm title bar.

      shell   Specifies the interpreter for executable scripts which do not
              themselves specify an interpreter.  The first word should be a
              full path name to the desired interpreter (e.g., `/bin/csh' or
              `/usr/local/bin/tcsh').

    Special shell variables
      The variables described in this section have special meaning to the
      shell.

      The shell sets addsuffix, argv, autologout, csubstnonl, command,
      echo_style, edit, gid, group, home, loginsh, oid, path, prompt,
      prompt2, prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
      at startup; they do not change thereafter unless changed by the user.
      The shell updates cwd, dirstack, owd and status when necessary, and
      sets logout on logout.

      The shell synchronizes group, home, path, shlvl, term and user with
      the environment variables of the same names: whenever the environment
      variable changes the shell changes the corresponding shell variable to
      match (unless the shell variable is read-only) and vice versa.  Note
      that although cwd and PWD have identical meanings, they are not
      synchronized in this manner, and that the shell automatically converts
      between the different formats of path and PATH.

      addsuffix (+)
              If set, filename completion adds `/' to the end of directories
              and a space to the end of normal files when they are matched
              exactly.  Set by default.

      afsuser (+)
              If set, autologout's autolock feature uses its value instead
              of the local username for kerberos authentication.

      ampm (+)
              If set, all times are shown in 12-hour AM/PM format.

      anyerror (+)
              This variable selects what is propagated to the value of the



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              status variable. For more information see the description of
              the status variable below.

      argv    The arguments to the shell.  Positional parameters are taken
              from argv, i.e., `$1' is replaced by `$argv[1]', etc.  Set by
              default, but usually empty in interactive shells.

      autocorrect (+)
              If set, the spell-word editor command is invoked automatically
              before each completion attempt.

      autoexpand (+)
              If set, the expand-history editor command is invoked
              automatically before each completion attempt. If this is set
              to onlyhistory, then only history will be expanded and a
              second completion will expand filenames.

      autolist (+)
              If set, possibilities are listed after an ambiguous
              completion.  If set to `ambiguous', possibilities are listed
              only when no new characters are added by completion.

      autologout (+)
              The first word is the number of minutes of inactivity before
              automatic logout.  The optional second word is the number of
              minutes of inactivity before automatic locking.  When the
              shell automatically logs out, it prints `auto-logout', sets
              the variable logout to `automatic' and exits.  When the shell
              automatically locks, the user is required to enter his
              password to continue working.  Five incorrect attempts result
              in automatic logout.  Set to `60' (automatic logout after 60
              minutes, and no locking) by default in login and superuser
              shells, but not if the shell thinks it is running under a
              window system (i.e., the DISPLAY environment variable is set),
              the tty is a pseudo-tty (pty) or the shell was not so compiled
              (see the version shell variable).  See also the afsuser and
              logout shell variables.

      autorehash (+)
              If set, the internal hash table of the contents of the
              directories in the path variable will be recomputed if a
              command is not found in the hash table.  In addition, the list
              of available commands will be rebuilt for each command
              completion or spelling correction attempt if set to `complete'
              or `correct' respectively; if set to `always', this will be
              done for both cases.

      backslash_quote (+)
              If set, backslashes (`\') always quote `\', `'', and `"'.
              This may make complex quoting tasks easier, but it can cause
              syntax errors in csh(1) scripts.



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      catalog The file name of the message catalog.  If set, tcsh use
              `tcsh.${catalog}' as a message catalog instead of default
              `tcsh'.

      cdpath  A list of directories in which cd should search for
              subdirectories if they aren't found in the current directory.

      cdtohome (+)
              If not set, cd requires a directory name, and will not go to
              the home directory if it's omitted.  This is set by default.

      color   If set, it enables color display for the builtin ls-F and it
              passes --color=auto to ls.  Alternatively, it can be set to
              only ls-F or only ls to enable color to only one command.
              Setting it to nothing is equivalent to setting it to (ls-F
              ls).

      colorcat
              If set, it enables color escape sequence for NLS message
              files.  And display colorful NLS messages.

      command (+)
              If set, the command which was passed to the shell with the -c
              flag (q.v.).

      compat_expr (+)
              If set, the shell will evaluate expressions right to left,
              like the original csh.

      complete (+)
              If set to `igncase', the completion becomes case insensitive.
              If set to `enhance', completion ignores case and considers
              hyphens and underscores to be equivalent; it will also treat
              periods, hyphens and underscores (`.', `-' and `_') as word
              separators.  If set to `Enhance', completion matches uppercase
              and underscore characters explicitly and matches lowercase and
              hyphens in a case-insensitive manner; it will treat periods,
              hyphens and underscores as word separators.

      continue (+)
              If set to a list of commands, the shell will continue the
              listed commands, instead of starting a new one.

      continue_args (+)
              Same as continue, but the shell will execute:

                  echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

      correct (+)
              If set to `cmd', commands are automatically spelling-
              corrected.  If set to `complete', commands are automatically



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              completed.  If set to `all', the entire command line is
              corrected.

      csubstnonl (+)
              If set, newlines and carriage returns in command substitution
              are replaced by spaces.  Set by default.

      cwd     The full pathname of the current directory.  See also the
              dirstack and owd shell variables.

      dextract (+)
              If set, `pushd +n' extracts the nth directory from the
              directory stack rather than rotating it to the top.

      dirsfile (+)
              The default location in which `dirs -S' and `dirs -L' look for
              a history file.  If unset, ~/.cshdirs is used.  Because only
              ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile
              should be set in ~/.tcshrc rather than ~/.login.

      dirstack (+)
              An array of all the directories on the directory stack.
              `$dirstack[1]' is the current working directory,
              `$dirstack[2]' the first directory on the stack, etc.  Note
              that the current working directory is `$dirstack[1]' but `=0'
              in directory stack substitutions, etc.  One can change the
              stack arbitrarily by setting dirstack, but the first element
              (the current working directory) is always correct.  See also
              the cwd and owd shell variables.

      dspmbyte (+)
              Has an effect iff 'dspm' is listed as part of the version
              shell variable.  If set to `euc', it enables display and
              editing EUC-kanji(Japanese) code.  If set to `sjis', it
              enables display and editing Shift-JIS(Japanese) code.  If set
              to `big5', it enables display and editing Big5(Chinese) code.
              If set to `utf8', it enables display and editing Utf8(Unicode)
              code.  If set to the following format, it enables display and
              editing of original multi-byte code format:

                  > set dspmbyte = 0000....(256 bytes)....0000

              The table requires just 256 bytes.  Each character of 256
              characters corresponds (from left to right) to the ASCII codes
              0x00, 0x01, ... 0xff.  Each character is set to number 0,1,2
              and 3.  Each number has the following meaning:
                0 ... not used for multi-byte characters.
                1 ... used for the first byte of a multi-byte character.
                2 ... used for the second byte of a multi-byte character.
                3 ... used for both the first byte and second byte of a
              multi-byte character.



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                Example:
              If set to `001322', the first character (means 0x00 of the
              ASCII code) and second character (means 0x01 of ASCII code)
              are set to `0'.  Then, it is not used for multi-byte
              characters.  The 3rd character (0x02) is set to '1',
              indicating that it is used for the first byte of a multi-byte
              character.  The 4th character(0x03) is set '3'.  It is used
              for both the first byte and the second byte of a multi-byte
              character.  The 5th and 6th characters (0x04,0x05) are set to
              '2', indicating that they are used for the second byte of a
              multi-byte character.

              The GNU fileutils version of ls cannot display multi-byte
              filenames without the -N ( --literal ) option.   If you are
              using this version, set the second word of dspmbyte to "ls".
              If not, for example, "ls-F -l" cannot display multi-byte
              filenames.

                Note:
              This variable can only be used if KANJI and DSPMBYTE has been
              defined at compile time.

      dunique (+)
              If set, pushd removes any instances of name from the stack
              before pushing it onto the stack.

      echo    If set, each command with its arguments is echoed just before
              it is executed.  For non-builtin commands all expansions occur
              before echoing.  Builtin commands are echoed before command
              and filename substitution, because these substitutions are
              then done selectively.  Set by the -x command line option.

      echo_style (+)
              The style of the echo builtin.  May be set to

              bsd     Don't echo a newline if the first argument is `-n';
                      the default for csh.
              sysv    Recognize backslashed escape sequences in echo
                      strings.
              both    Recognize both the `-n' flag and backslashed escape
                      sequences; the default for tcsh.
              none    Recognize neither.

              Set by default to the local system default.  The BSD and
              System V options are described in the echo(1) man pages on the
              appropriate systems.

      edit (+)
              If set, the command-line editor is used.  Set by default in
              interactive shells.




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      editors (+)
              A list of command names for the run-fg-editor editor command
              to match.  If not set, the EDITOR (`ed' if unset) and VISUAL
              (`vi' if unset) environment variables will be used instead.

      ellipsis (+)
              If set, the `%c'/`%.' and `%C' prompt sequences (see the
              prompt shell variable) indicate skipped directories with an
              ellipsis (`...') instead of `/<skipped>'.

      euid (+)
              The user's effective user ID.

      euser (+)
              The first matching passwd entry name corresponding to the
              effective user ID.

      fignore (+)
              Lists file name suffixes to be ignored by completion.

      filec   In tcsh, completion is always used and this variable is
              ignored by default. If edit is unset, then the traditional csh
              completion is used.  If set in csh, filename completion is
              used.

      gid (+) The user's real group ID.

      globdot (+)
              If set, wild-card glob patterns will match files and
              directories beginning with `.' except for `.' and `..'

      globstar (+)
              If set, the `**' and `***' file glob patterns will match any
              string of characters including `/' traversing any existing
              sub-directories.  (e.g. `ls **.c' will list all the .c files
              in the current directory tree).  If used by itself, it will
              match zero or more sub-directories (e.g. `ls
              /usr/include/**/time.h' will list any file named `time.h' in
              the /usr/include directory tree; whereas `ls
              /usr/include/**time.h' will match any file in the /usr/include
              directory tree ending in `time.h').  To prevent problems with
              recursion, the `**' glob-pattern will not descend into a
              symbolic link containing a directory.  To override this, use
              `***'

      group (+)
              The user's group name.

      highlight
              If set, the incremental search match (in i-search-back and i-
              search-fwd) and the region between the mark and the cursor are



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              highlighted in reverse video.

              Highlighting requires more frequent terminal writes, which
              introduces extra overhead. If you care about terminal
              performance, you may want to leave this unset.

      histchars
              A string value determining the characters used in History
              substitution (q.v.).  The first character of its value is used
              as the history substitution character, replacing the default
              character `!'.  The second character of its value replaces the
              character `^' in quick substitutions.

      histdup (+)
              Controls handling of duplicate entries in the history list.
              If set to `all' only unique history events are entered in the
              history list.  If set to `prev' and the last history event is
              the same as the current command, then the current command is
              not entered in the history.  If set to `erase' and the same
              event is found in the history list, that old event gets erased
              and the current one gets inserted.  Note that the `prev' and
              `all' options renumber history events so there are no gaps.

      histfile (+)
              The default location in which `history -S' and `history -L'
              look for a history file.  If unset, ~/.history is used.
              histfile is useful when sharing the same home directory
              between different machines, or when saving separate histories
              on different terminals.  Because only ~/.tcshrc is normally
              sourced before ~/.history, histfile should be set in ~/.tcshrc
              rather than ~/.login.

      histlit (+)
              If set, builtin and editor commands and the savehist mechanism
              use the literal (unexpanded) form of lines in the history
              list.  See also the toggle-literal-history editor command.

      history The first word indicates the number of history events to save.
              The optional second word (+) indicates the format in which
              history is printed; if not given, `%h\t%T\t%R\n' is used.  The
              format sequences are described below under prompt; note the
              variable meaning of `%R'.  Set to `100' by default.

      home    Initialized to the home directory of the invoker.  The
              filename expansion of `~' refers to this variable.

      ignoreeof
              If set to the empty string or `0' and the input device is a
              terminal, the end-of-file command (usually generated by the
              user by typing `^D' on an empty line) causes the shell to
              print `Use "exit" to leave tcsh.' instead of exiting.  This



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              prevents the shell from accidentally being killed.
              Historically this setting exited after 26 successive EOF's to
              avoid infinite loops.  If set to a number n, the shell ignores
              n - 1 consecutive end-of-files and exits on the nth.  (+) If
              unset, `1' is used, i.e., the shell exits on a single `^D'.

      implicitcd (+)
              If set, the shell treats a directory name typed as a command
              as though it were a request to change to that directory.  If
              set to verbose, the change of directory is echoed to the
              standard output.  This behavior is inhibited in non-
              interactive shell scripts, or for command strings with more
              than one word.  Changing directory takes precedence over
              executing a like-named command, but it is done after alias
              substitutions.  Tilde and variable expansions work as
              expected.

      inputmode (+)
              If set to `insert' or `overwrite', puts the editor into that
              input mode at the beginning of each line.

      killdup (+)
              Controls handling of duplicate entries in the kill ring.  If
              set to `all' only unique strings are entered in the kill ring.
              If set to `prev' and the last killed string is the same as the
              current killed string, then the current string is not entered
              in the ring.  If set to `erase' and the same string is found
              in the kill ring, the old string is erased and the current one
              is inserted.

      killring (+)
              Indicates the number of killed strings to keep in memory.  Set
              to `30' by default.  If unset or set to less than `2', the
              shell will only keep the most recently killed string.  Strings
              are put in the killring by the editor commands that delete
              (kill) strings of text, e.g. backward-delete-word, kill-line,
              etc, as well as the copy-region-as-kill command.  The yank
              editor command will yank the most recently killed string into
              the command-line, while yank-pop (see Editor commands) can be
              used to yank earlier killed strings.

      listflags (+)
              If set to `x', `a' or `A', or any combination thereof (e.g.,
              `xA'), they are used as flags to ls-F, making it act like `ls
              -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'):
              `a' shows all files (even if they start with a `.'), `A' shows
              all files but `.' and `..', and `x' sorts across instead of
              down.  If the second word of listflags is set, it is used as
              the path to `ls(1)'.





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      listjobs (+)
              If set, all jobs are listed when a job is suspended.  If set
              to `long', the listing is in long format.

      listlinks (+)
              If set, the ls-F builtin command shows the type of file to
              which each symbolic link points.

      listmax (+)
              The maximum number of items which the list-choices editor
              command will list without asking first.

      listmaxrows (+)
              The maximum number of rows of items which the list-choices
              editor command will list without asking first.

      loginsh (+)
              Set by the shell if it is a login shell.  Setting or unsetting
              it within a shell has no effect.  See also shlvl.

      logout (+)
              Set by the shell to `normal' before a normal logout,
              `automatic' before an automatic logout, and `hangup' if the
              shell was killed by a hangup signal (see Signal handling).
              See also the autologout shell variable.

      mail    A list of files and directories to check for incoming mail,
              optionally preceded by a numeric word.  Before each prompt, if
              10 minutes have passed since the last check, the shell checks
              each file and says `You have new mail.' (or, if mail contains
              multiple files, `You have new mail in name.') if the filesize
              is greater than zero in size and has a modification time
              greater than its access time.

              If you are in a login shell, then no mail file is reported
              unless it has been modified after the time the shell has
              started up, to prevent redundant notifications.  Most login
              programs will tell you whether or not you have mail when you
              log in.

              If a file specified in mail is a directory, the shell will
              count each file within that directory as a separate message,
              and will report `You have n mails.' or `You have n mails in
              name.' as appropriate.  This functionality is provided
              primarily for those systems which store mail in this manner,
              such as the Andrew Mail System.

              If the first word of mail is numeric it is taken as a
              different mail checking interval, in seconds.





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              Under very rare circumstances, the shell may report `You have
              mail.' instead of `You have new mail.'

      matchbeep (+)
              If set to `never', completion never beeps.  If set to
              `nomatch', it beeps only when there is no match.  If set to
              `ambiguous', it beeps when there are multiple matches.  If set
              to `notunique', it beeps when there is one exact and other
              longer matches.  If unset, `ambiguous' is used.

      nobeep (+)
              If set, beeping is completely disabled.  See also visiblebell.

      noclobber
              If set, restrictions are placed on output redirection to
              insure that files are not accidentally destroyed and that `>>'
              redirections refer to existing files, as described in the
              Input/output section.

      noding  If set, disable the printing of `DING!' in the prompt time
              specifiers at the change of hour.

      noglob  If set, Filename substitution and Directory stack substitution
              (q.v.) are inhibited.  This is most useful in shell scripts
              which do not deal with filenames, or after a list of filenames
              has been obtained and further expansions are not desirable.

      nokanji (+)
              If set and the shell supports Kanji (see the version shell
              variable), it is disabled so that the meta key can be used.

      nonomatch
              If set, a Filename substitution or Directory stack
              substitution (q.v.) which does not match any existing files is
              left untouched rather than causing an error.  It is still an
              error for the substitution to be malformed, e.g., `echo ['
              still gives an error.

      nostat (+)
              A list of directories (or glob-patterns which match
              directories; see Filename substitution) that should not be
              stat(2)ed during a completion operation.  This is usually used
              to exclude directories which take too much time to stat(2),
              for example /afs.

      notify  If set, the shell announces job completions asynchronously.
              The default is to present job completions just before printing
              a prompt.

      oid (+) The user's real organization ID.  (Domain/OS only)




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      owd (+) The old working directory, equivalent to the `-' used by cd
              and pushd.  See also the cwd and dirstack shell variables.

      padhour If set, enable the printing of padding '0' for hours, in 24
              and 12 hour formats.  E.G.: 07:45:42 vs. 7:45:42.

      parseoctal
              To retain compatibily with older versions numeric variables
              starting with 0 are not interpreted as octal. Setting this
              variable enables proper octal parsing.

      path    A list of directories in which to look for executable
              commands.  A null word specifies the current directory.  If
              there is no path variable then only full path names will
              execute.  path is set by the shell at startup from the PATH
              environment variable or, if PATH does not exist, to a system-
              dependent default something like `(/usr/local/bin /usr/bsd
              /bin /usr/bin .)'.  The shell may put `.' first or last in
              path or omit it entirely depending on how it was compiled; see
              the version shell variable.  A shell which is given neither
              the -c nor the -t option hashes the contents of the
              directories in path after reading ~/.tcshrc and each time path
              is reset.  If one adds a new command to a directory in path
              while the shell is active, one may need to do a rehash for the
              shell to find it.

      printexitvalue (+)
              If set and an interactive program exits with a non-zero
              status, the shell prints `Exit status'.

      prompt  The string which is printed before reading each command from
              the terminal.  prompt may include any of the following
              formatting sequences (+), which are replaced by the given
              information:

              %/  The current working directory.
              %~  The current working directory, but with one's home
                  directory represented by `~' and other users' home
                  directories represented by `~user' as per Filename
                  substitution.  `~user' substitution happens only if the
                  shell has already used `~user' in a pathname in the
                  current session.
              %c[[0]n], %.[[0]n]
                  The trailing component of the current working directory,
                  or n trailing components if a digit n is given.  If n
                  begins with `0', the number of skipped components precede
                  the trailing component(s) in the format
                  `/<skipped>trailing'.  If the ellipsis shell variable is
                  set, skipped components are represented by an ellipsis so
                  the whole becomes `...trailing'.  `~' substitution is done
                  as in `%~' above, but the `~' component is ignored when



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                  counting trailing components.
              %C  Like %c, but without `~' substitution.
              %h, %!, !
                  The current history event number.
              %M  The full hostname.
              %m  The hostname up to the first `.'.
              %S (%s)
                  Start (stop) standout mode.
              %B (%b)
                  Start (stop) boldfacing mode.
              %U (%u)
                  Start (stop) underline mode.
              %t, %@
                  The time of day in 12-hour AM/PM format.
              %T  Like `%t', but in 24-hour format (but see the ampm shell
                  variable).
              %p  The `precise' time of day in 12-hour AM/PM format, with
                  seconds.
              %P  Like `%p', but in 24-hour format (but see the ampm shell
                  variable).
              \c  c is parsed as in bindkey.
              ^c  c is parsed as in bindkey.
              %%  A single `%'.
              %n  The user name.
              %N  The effective user name.
              %j  The number of jobs.
              %d  The weekday in `Day' format.
              %D  The day in `dd' format.
              %w  The month in `Mon' format.
              %W  The month in `mm' format.
              %y  The year in `yy' format.
              %Y  The year in `yyyy' format.
              %l  The shell's tty.
              %L  Clears from the end of the prompt to end of the display or
                  the end of the line.
              %$  Expands the shell or environment variable name immediately
                  after the `$'.
              %#  `>' (or the first character of the promptchars shell
                  variable) for normal users, `#' (or the second character
                  of promptchars) for the superuser.
              %{string%}
                  Includes string as a literal escape sequence.  It should
                  be used only to change terminal attributes and should not
                  move the cursor location.  This cannot be the last
                  sequence in prompt.
              %?  The return code of the command executed just before the
                  prompt.
              %R  In prompt2, the status of the parser.  In prompt3, the
                  corrected string.  In history, the history string.





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              `%B', `%S', `%U' and `%{string%}' are available in only
              eight-bit-clean shells; see the version shell variable.

              The bold, standout and underline sequences are often used to
              distinguish a superuser shell.  For example,

                  > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                  tut [37] [2:54pm] [/usr/accts/sys] you rang? _

              If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
              set, then print `DING!' on the change of hour (i.e, `:00'
              minutes) instead of the actual time.

              Set by default to `%# ' in interactive shells.

      prompt2 (+)
              The string with which to prompt in while and foreach loops and
              after lines ending in `\'.  The same format sequences may be
              used as in prompt (q.v.); note the variable meaning of `%R'.
              Set by default to `%R? ' in interactive shells.

      prompt3 (+)
              The string with which to prompt when confirming automatic
              spelling correction.  The same format sequences may be used as
              in prompt (q.v.); note the variable meaning of `%R'.  Set by
              default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

      promptchars (+)
              If set (to a two-character string), the `%#' formatting
              sequence in the prompt shell variable is replaced with the
              first character for normal users and the second character for
              the superuser.

      pushdtohome (+)
              If set, pushd without arguments does `pushd ~', like cd.

      pushdsilent (+)
              If set, pushd and popd do not print the directory stack.

      recexact (+)
              If set, completion completes on an exact match even if a
              longer match is possible.

      recognize_only_executables (+)
              If set, command listing displays only files in the path that
              are executable.  Slow.

      rmstar (+)
              If set, the user is prompted before `rm *' is executed.





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      rprompt (+)
              The string to print on the right-hand side of the screen
              (after the command input) when the prompt is being displayed
              on the left.  It recognizes the same formatting characters as
              prompt.  It will automatically disappear and reappear as
              necessary, to ensure that command input isn't obscured, and
              will appear only if the prompt, command input, and itself will
              fit together on the first line.  If edit isn't set, then
              rprompt will be printed after the prompt and before the
              command input.

      savedirs (+)
              If set, the shell does `dirs -S' before exiting.  If the first
              word is set to a number, at most that many directory stack
              entries are saved.

      savehist
              If set, the shell does `history -S' before exiting.  If the
              first word is set to a number, at most that many lines are
              saved.  (The number should be less than or equal to the number
              history entries; if it is set to greater than the number of
              history settings, only history entries will be saved) If the
              second word is set to `merge', the history list is merged with
              the existing history file instead of replacing it (if there is
              one) and sorted by time stamp and the most recent events are
              retained.  If the second word of savehist is `merge' and the
              third word is set to `lock', the history file update will be
              serialized with other shell sessions that would possibly like
              to merge history at exactly the same time. (+)

      sched (+)
              The format in which the sched builtin command prints scheduled
              events; if not given, `%h\t%T\t%R\n' is used.  The format
              sequences are described above under prompt; note the variable
              meaning of `%R'.

      shell   The file in which the shell resides.  This is used in forking
              shells to interpret files which have execute bits set, but
              which are not executable by the system.  (See the description
              of Builtin and non-builtin command execution.)  Initialized to
              the (system-dependent) home of the shell.

      shlvl (+)
              The number of nested shells.  Reset to 1 in login shells.  See
              also loginsh.

      status  The exit status from the last command or backquote expansion,
              or any command in a pipeline is propagated to status.  (This
              is also the default csh behavior.) This default does not match
              what POSIX mandates (to return the status of the last command
              only). To match the POSIX behavior, you need to unset



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              anyerror.

              If the anyerror variable is unset, the exit status of a
              pipeline is determined only from the last command in the
              pipeline, and the exit status of a backquote expansion is not
              propagated to status.

              If a command terminated abnormally, then 0200 is added to the
              status.  Builtin commands which fail return exit status `1',
              all other builtin commands return status `0'.

      symlinks (+)
              Can be set to several different values to control symbolic
              link (`symlink') resolution:

              If set to `chase', whenever the current directory changes to a
              directory containing a symbolic link, it is expanded to the
              real name of the directory to which the link points.  This
              does not work for the user's home directory; this is a bug.

              If set to `ignore', the shell tries to construct a current
              directory relative to the current directory before the link
              was crossed.  This means that cding through a symbolic link
              and then `cd ..'ing returns one to the original directory.
              This affects only builtin commands and filename completion.

              If set to `expand', the shell tries to fix symbolic links by
              actually expanding arguments which look like path names.  This
              affects any command, not just builtins.  Unfortunately, this
              does not work for hard-to-recognize filenames, such as those
              embedded in command options.  Expansion may be prevented by
              quoting.  While this setting is usually the most convenient,
              it is sometimes misleading and sometimes confusing when it
              fails to recognize an argument which should be expanded.  A
              compromise is to use `ignore' and use the editor command
              normalize-path (bound by default to ^X-n) when necessary.

              Some examples are in order.  First, let's set up some play
              directories:

                  > cd /tmp
                  > mkdir from from/src to
                  > ln -s from/src to/dst

              Here's the behavior with symlinks unset,

                  > cd /tmp/to/dst; echo $cwd
                  /tmp/to/dst
                  > cd ..; echo $cwd
                  /tmp/from




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              here's the behavior with symlinks set to `chase',

                  > cd /tmp/to/dst; echo $cwd
                  /tmp/from/src
                  > cd ..; echo $cwd
                  /tmp/from

              here's the behavior with symlinks set to `ignore',

                  > cd /tmp/to/dst; echo $cwd
                  /tmp/to/dst
                  > cd ..; echo $cwd
                  /tmp/to

              and here's the behavior with symlinks set to `expand'.

                  > cd /tmp/to/dst; echo $cwd
                  /tmp/to/dst
                  > cd ..; echo $cwd
                  /tmp/to
                  > cd /tmp/to/dst; echo $cwd
                  /tmp/to/dst
                  > cd ".."; echo $cwd
                  /tmp/from
                  > /bin/echo ..
                  /tmp/to
                  > /bin/echo ".."
                  ..

              Note that `expand' expansion 1) works just like `ignore' for
              builtins like cd, 2) is prevented by quoting, and 3) happens
              before filenames are passed to non-builtin commands.

      tcsh (+)
              The version number of the shell in the format `R.VV.PP', where
              `R' is the major release number, `VV' the current version and
              `PP' the patchlevel.

      term    The terminal type.  Usually set in ~/.login as described under
              Startup and shutdown.

      time    If set to a number, then the time builtin (q.v.) executes
              automatically after each command which takes more than that
              many CPU seconds.  If there is a second word, it is used as a
              format string for the output of the time builtin.  (u) The
              following sequences may be used in the format string:

              %U  The time the process spent in user mode in cpu seconds.
              %S  The time the process spent in kernel mode in cpu seconds.
              %E  The elapsed (wall clock) time in seconds.




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              %P  The CPU percentage computed as (%U + %S) / %E.
              %W  Number of times the process was swapped.
              %X  The average amount in (shared) text space used in Kbytes.
              %D  The average amount in (unshared) data/stack space used in
                  Kbytes.
              %K  The total space used (%X + %D) in Kbytes.
              %M  The maximum memory the process had in use at any time in
                  Kbytes.
              %F  The number of major page faults (page needed to be brought
                  from disk).
              %R  The number of minor page faults.
              %I  The number of input operations.
              %O  The number of output operations.
              %r  The number of socket messages received.
              %s  The number of socket messages sent.
              %k  The number of signals received.
              %w  The number of voluntary context switches (waits).
              %c  The number of involuntary context switches.

              Only the first four sequences are supported on systems without
              BSD resource limit functions.  The default time format is `%Uu
              %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
              resource usage reporting and `%Uu %Ss %E %P' for systems that
              do not.

              Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not
              available, but the following additional sequences are:

              %Y  The number of system calls performed.
              %Z  The number of pages which are zero-filled on demand.
              %i  The number of times a process's resident set size was
                  increased by the kernel.
              %d  The number of times a process's resident set size was
                  decreased by the kernel.
              %l  The number of read system calls performed.
              %m  The number of write system calls performed.
              %p  The number of reads from raw disk devices.
              %q  The number of writes to raw disk devices.

              and the default time format is `%Uu %Ss %E %P %I+%Oio
              %Fpf+%Ww'.  Note that the CPU percentage can be higher than
              100% on multi-processors.

      tperiod (+)
              The period, in minutes, between executions of the periodic
              special alias.

      tty (+) The name of the tty, or empty if not attached to one.

      uid (+) The user's real user ID.




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      user    The user's login name.

      verbose If set, causes the words of each command to be printed, after
              history substitution (if any).  Set by the -v command line
              option.

      version (+)
              The version ID stamp.  It contains the shell's version number
              (see tcsh), origin, release date, vendor, operating system and
              machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-
              separated list of options which were set at compile time.
              Options which are set by default in the distribution are
              noted.

              8b    The shell is eight bit clean; default
              7b    The shell is not eight bit clean
              wide  The shell is multibyte encoding clean (like UTF-8)
              nls   The system's NLS is used; default for systems with NLS
              lf    Login shells execute /etc/csh.login before instead of
                    after /etc/csh.cshrc and ~/.login before instead of
                    after ~/.tcshrc and ~/.history.
              dl    `.' is put last in path for security; default
              nd    `.' is omitted from path for security
              vi    vi(1)-style editing is the default rather than
                    emacs(1)-style
              dtr   Login shells drop DTR when exiting
              bye   bye is a synonym for logout and log is an alternate name
                    for watchlog
              al    autologout is enabled; default
              kan   Kanji is used if appropriate according to locale
                    settings, unless the nokanji shell variable is set
              sm    The system's malloc(3) is used
              hb    The `#!<program> <args>' convention is emulated when
                    executing shell scripts
              ng    The newgrp builtin is available
              rh    The shell attempts to set the REMOTEHOST environment
                    variable
              afs   The shell verifies your password with the kerberos
                    server if local authentication fails.  The afsuser shell
                    variable or the AFSUSER environment variable override
                    your local username if set.

              An administrator may enter additional strings to indicate
              differences in the local version.

      vimode (+)
              If unset, various key bindings change behavior to be more
              emacs(1)-style: word boundaries are determined by wordchars
              versus other characters.





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              If set, various key bindings change behavior to be more
              vi(1)-style: word boundaries are determined by wordchars
              versus whitespace versus other characters; cursor behavior
              depends upon current vi mode (command, delete, insert,
              replace).

              This variable is unset by bindkey -e and set by bindkey -v.
              vimode may be explicitly set or unset by the user after those
              bindkey operations if required.

      visiblebell (+)
              If set, a screen flash is used rather than the audible bell.
              See also nobeep.

      watch (+)
              A list of user/terminal pairs to watch for logins and logouts.
              If either the user is `any' all terminals are watched for the
              given user and vice versa.  Setting watch to `(any any)'
              watches all users and terminals.  For example,

                  set watch = (george ttyd1 any console $user any)

              reports activity of the user `george' on ttyd1, any user on
              the console, and oneself (or a trespasser) on any terminal.

              Logins and logouts are checked every 10 minutes by default,
              but the first word of watch can be set to a number to check
              every so many minutes.  For example,

                  set watch = (1 any any)

              reports any login/logout once every minute.  For the
              impatient, the log builtin command triggers a watch report at
              any time.  All current logins are reported (as with the log
              builtin) when watch is first set.

              The who shell variable controls the format of watch reports.

      who (+) The format string for watch messages.  The following sequences
              are replaced by the given information:

              %n  The name of the user who logged in/out.
              %a  The observed action, i.e., `logged on', `logged off' or
                  `replaced olduser on'.
              %l  The terminal (tty) on which the user logged in/out.
              %M  The full hostname of the remote host, or `local' if the
                  login/logout was from the local host.
              %m  The hostname of the remote host up to the first `.'.  The
                  full name is printed if it is an IP address or an X Window
                  System display.




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              %M and %m are available on only systems that store the remote
              hostname in /etc/utmp.  If unset, `%n has %a %l from %m.' is
              used, or `%n has %a %l.' on systems which don't store the
              remote hostname.

      wordchars (+)
              A list of non-alphanumeric characters to be considered part of
              a word by the forward-word, backward-word etc., editor
              commands.  If unset, the default value is determined based on
              the state of vimode: if vimode is unset, `*?_-.[]~=' is used
              as the default; if vimode is set, `_' is used as the default.

 ENVIRONMENT
      AFSUSER (+)
              Equivalent to the afsuser shell variable.

      COLUMNS The number of columns in the terminal.  See Terminal
              management.

      DISPLAY Used by X Window System (see X(1)).  If set, the shell does
              not set autologout (q.v.).

      EDITOR  The pathname to a default editor.  Used by the run-fg-editor
              editor command if the the editors shell variable is unset.
              See also the VISUAL environment variable.

      GROUP (+)
              Equivalent to the group shell variable.

      HOME    Equivalent to the home shell variable.

      HOST (+)
              Initialized to the name of the machine on which the shell is
              running, as determined by the gethostname(2) system call.

      HOSTTYPE (+)
              Initialized to the type of machine on which the shell is
              running, as determined at compile time.  This variable is
              obsolete and will be removed in a future version.

      HPATH (+)
              A colon-separated list of directories in which the run-help
              editor command looks for command documentation.

      LANG    Gives the preferred character environment.  See Native
              Language System support.

      LC_CTYPE
              If set, only ctype character handling is changed.  See Native
              Language System support.




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      LINES   The number of lines in the terminal.  See Terminal management.

      LS_COLORS
              The format of this variable is reminiscent of the termcap(5)
              file format; a colon-separated list of expressions of the form
              "xx=string", where "xx" is a two-character variable name.  The
              variables with their associated defaults are:

                  no   0      Normal (non-filename) text
                  fi   0      Regular file
                  di   01;34  Directory
                  ln   01;36  Symbolic link
                  pi   33     Named pipe (FIFO)
                  so   01;35  Socket
                  do   01;35  Door
                  bd   01;33  Block device
                  cd   01;32  Character device
                  ex   01;32  Executable file
                  mi   (none) Missing file (defaults to fi)
                  or   (none) Orphaned symbolic link (defaults to ln)
                  lc   ^[[    Left code
                  rc   m      Right code
                  ec   (none) End code (replaces lc+no+rc)

              You need to include only the variables you want to change from
              the default.

              File names can also be colorized based on filename extension.
              This is specified in the LS_COLORS variable using the syntax
              "*ext=string".  For example, using ISO 6429 codes, to color
              all C-language source files blue you would specify "*.c=34".
              This would color all files ending in .c in blue (34) color.

              Control characters can be written either in C-style-escaped
              notation, or in stty-like ^-notation.  The C-style notation
              adds ^[ for Escape, _ for a normal space character, and ? for
              Delete.  In addition, the ^[ escape character can be used to
              override the default interpretation of ^[, ^, : and =.

              Each file will be written as <lc> <color-code> <rc> <filename>
              <ec>.  If the <ec> code is undefined, the sequence <lc> <no>
              <rc> will be used instead.  This is generally more convenient
              to use, but less general.  The left, right and end codes are
              provided so you don't have to type common parts over and over
              again and to support weird terminals; you will generally not
              need to change them at all unless your terminal does not use
              ISO 6429 color sequences but a different system.

              If your terminal does use ISO 6429 color codes, you can
              compose the type codes (i.e., all except the lc, rc, and ec
              codes) from numerical commands separated by semicolons.  The



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              most common commands are:

                      0   to restore default color
                      1   for brighter colors
                      4   for underlined text
                      5   for flashing text
                      30  for black foreground
                      31  for red foreground
                      32  for green foreground
                      33  for yellow (or brown) foreground
                      34  for blue foreground
                      35  for purple foreground
                      36  for cyan foreground
                      37  for white (or gray) foreground
                      40  for black background
                      41  for red background
                      42  for green background
                      43  for yellow (or brown) background
                      44  for blue background
                      45  for purple background
                      46  for cyan background
                      47  for white (or gray) background

              Not all commands will work on all systems or display devices.

              A few terminal programs do not recognize the default end code
              properly.  If all text gets colorized after you do a directory
              listing, try changing the no and fi codes from 0 to the
              numerical codes for your standard fore- and background colors.

      MACHTYPE (+)
              The machine type (microprocessor class or machine model), as
              determined at compile time.

      NOREBIND (+)
              If set, printable characters are not rebound to self-insert-
              command.  See Native Language System support.

      OSTYPE (+)
              The operating system, as determined at compile time.

      PATH    A colon-separated list of directories in which to look for
              executables.  Equivalent to the path shell variable, but in a
              different format.

      PWD (+) Equivalent to the cwd shell variable, but not synchronized to
              it; updated only after an actual directory change.

      REMOTEHOST (+)
              The host from which the user has logged in remotely, if this
              is the case and the shell is able to determine it.  Set only



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              if the shell was so compiled; see the version shell variable.

      SHLVL (+)
              Equivalent to the shlvl shell variable.

      SYSTYPE (+)
              The current system type.  (Domain/OS only)

      TERM    Equivalent to the term shell variable.

      TERMCAP The terminal capability string.  See Terminal management.

      USER    Equivalent to the user shell variable.

      VENDOR (+)
              The vendor, as determined at compile time.

      VISUAL  The pathname to a default full-screen editor.  Used by the
              run-fg-editor editor command if the the editors shell variable
              is unset.  See also the EDITOR environment variable.

 FILES
      /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and
                      Intel use /etc/cshrc and NeXTs use /etc/cshrc.std.
                      A/UX, AMIX, Cray and IRIX have no equivalent in
                      csh(1), but read this file in tcsh anyway.  Solaris
                      2.x does not have it either, but tcsh reads
                      /etc/.cshrc.  (+)
      /etc/csh.login  Read by login shells after /etc/csh.cshrc.  ConvexOS,
                      Stellix and Intel use /etc/login, NeXTs use
                      /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
                      AMIX, Cray and IRIX use /etc/cshrc.
      ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its
                      equivalent.
      ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist, after
                      /etc/csh.cshrc or its equivalent.  This manual uses
                      `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
                      found, ~/.cshrc'.
      ~/.history      Read by login shells after ~/.tcshrc if savehist is
                      set, but see also histfile.
      ~/.login        Read by login shells after ~/.tcshrc or ~/.history.
                      The shell may be compiled to read ~/.login before
                      instead of after ~/.tcshrc and ~/.history; see the
                      version shell variable.
      ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is
                      set, but see also dirsfile.
      /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix and
                      Intel use /etc/logout and NeXTs use /etc/logout.std.
                      A/UX, AMIX, Cray and IRIX have no equivalent in
                      csh(1), but read this file in tcsh anyway.  Solaris
                      2.x does not have it either, but tcsh reads



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                      /etc/.logout.  (+)
      ~/.logout       Read by login shells at logout after /etc/csh.logout
                      or its equivalent.
      /bin/sh         Used to interpret shell scripts not starting with a
                      `#'.
      /tmp/sh*        Temporary file for `<<'.
      /etc/passwd     Source of home directories for `~name' substitutions.

      The order in which startup files are read may differ if the shell was
      so compiled; see Startup and shutdown and the version shell variable.

 NEW FEATURES (+)
      This manual describes tcsh as a single entity, but experienced csh(1)
      users will want to pay special attention to tcsh's new features.

      A command-line editor, which supports emacs(1)-style or vi(1)-style
      key bindings.  See The command-line editor and Editor commands.

      Programmable, interactive word completion and listing.  See Completion
      and listing and the complete and uncomplete builtin commands.

      Spelling correction (q.v.) of filenames, commands and variables.

      Editor commands (q.v.) which perform other useful functions in the
      middle of typed commands, including documentation lookup (run-help),
      quick editor restarting (run-fg-editor) and command resolution
      (which-command).

      An enhanced history mechanism.  Events in the history list are time-
      stamped.  See also the history command and its associated shell
      variables, the previously undocumented `#' event specifier and new
      modifiers under History substitution, the *-history, history-search-*,
      i-search-*, vi-search-* and toggle-literal-history editor commands and
      the histlit shell variable.

      Enhanced directory parsing and directory stack handling.  See the cd,
      pushd, popd and dirs commands and their associated shell variables,
      the description of Directory stack substitution, the dirstack, owd and
      symlinks shell variables and the normalize-command and normalize-path
      editor commands.

      Negation in glob-patterns.  See Filename substitution.

      New File inquiry operators (q.v.) and a filetest builtin which uses
      them.

      A variety of Automatic, periodic and timed events (q.v.) including
      scheduled events, special aliases, automatic logout and terminal
      locking, command timing and watching for logins and logouts.





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      Support for the Native Language System (see Native Language System
      support), OS variant features (see OS variant support and the
      echo_style shell variable) and system-dependent file locations (see
      FILES).

      Extensive terminal-management capabilities.  See Terminal management.

      New builtin commands including builtins, hup, ls-F, newgrp, printenv,
      which and where (q.v.).

      New variables that make useful information easily available to the
      shell.  See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version
      shell variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
      environment variables.

      A new syntax for including useful information in the prompt string
      (see prompt), and special prompts for loops and spelling correction
      (see prompt2 and prompt3).

      Read-only variables.  See Variable substitution.

 BUGS
      When a suspended command is restarted, the shell prints the directory
      it started in if this is different from the current directory.  This
      can be misleading (i.e., wrong) as the job may have changed
      directories internally.

      Shell builtin functions are not stoppable/restartable.  Command
      sequences of the form `a ; b ; c' are also not handled gracefully when
      stopping is attempted.  If you suspend `b', the shell will then
      immediately execute `c'.  This is especially noticeable if this
      expansion results from an alias.  It suffices to place the sequence of
      commands in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.

      Control over tty output after processes are started is primitive;
      perhaps this will inspire someone to work on a good virtual terminal
      interface.  In a virtual terminal interface much more interesting
      things could be done with output control.

      Alias substitution is most often used to clumsily simulate shell
      procedures; shell procedures should be provided rather than aliases.

      Control structures should be parsed rather than being recognized as
      built-in commands.  This would allow control commands to be placed
      anywhere, to be combined with `|', and to be used with `&' and `;'
      metasyntax.

      foreach doesn't ignore here documents when looking for its end.

      It should be possible to use the `:' modifiers on the output of
      command substitutions.



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      The screen update for lines longer than the screen width is very poor
      if the terminal cannot move the cursor up (i.e., terminal type
      `dumb').

      HPATH and NOREBIND don't need to be environment variables.

      Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or
      `~' are not negated correctly.

      The single-command form of if does output redirection even if the
      expression is false and the command is not executed.

      ls-F includes file identification characters when sorting filenames
      and does not handle control characters in filenames well.  It cannot
      be interrupted.

      Command substitution supports multiple commands and conditions, but
      not cycles or backward gotos.

      Report bugs at http://bugs.gw.com/, preferably with fixes.  If you
      want to help maintain and test tcsh, send mail to tcsh-
      request@mx.gw.com with the text `subscribe tcsh' on a line by itself
      in the body.

 THE T IN TCSH
      In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-
      implementation.  It was re-christened the DECsystem-10 in 1970 or so
      when DEC brought out the second model, the KI10.

      TENEX was created at Bolt, Beranek & Newman (a Cambridge,
      Massachusetts think tank) in 1972 as an experiment in demand-paged
      virtual memory operating systems.  They built a new pager for the DEC
      PDP-10 and created the OS to go with it.  It was extremely successful
      in academia.

      In 1975, DEC brought out a new model of the PDP-10, the KL10; they
      intended to have only a version of TENEX, which they had licensed from
      BBN, for the new box.  They called their version TOPS-20 (their
      capitalization is trademarked).  A lot of TOPS-10 users (`The
      OPerating System for PDP-10') objected; thus DEC found themselves
      supporting two incompatible systems on the same hardware--but then
      there were 6 on the PDP-11!

      TENEX, and TOPS-20 to version 3, had command completion via a user-
      code-level subroutine library called ULTCMD.  With version 3, DEC
      moved all that capability and more into the monitor (`kernel' for you
      Unix types), accessed by the COMND% JSYS (`Jump to SYStem'
      instruction, the supervisor call mechanism [are my IBM roots also
      showing?]).





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      The creator of tcsh was impressed by this feature and several others
      of TENEX and TOPS-20, and created a version of csh which mimicked
      them.

 LIMITATIONS
      The system limits argument lists to ARG_MAX characters.

      The number of arguments to a command which involves filename expansion
      is limited to 1/6th the number of characters allowed in an argument
      list.

      Command substitutions may substitute no more characters than are
      allowed in an argument list.

      To detect looping, the shell restricts the number of alias
      substitutions on a single line to 20.

 SEE ALSO
      csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
      tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2),
      pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2),
      wait(2), malloc(3), setlocale(3), tty(4), a.out(5), termcap(5),
      environ(7), termio(7), Introduction to the C Shell

 VERSION
      This manual documents tcsh 6.20.00 (Astron) 2016-11-24.

 AUTHORS
      William Joy
        Original author of csh(1)
      J.E. Kulp, IIASA, Laxenburg, Austria
        Job control and directory stack features
      Ken Greer, HP Labs, 1981
        File name completion
      Mike Ellis, Fairchild, 1983
        Command name recognition/completion
      Paul Placeway, Ohio State CIS Dept., 1983-1993
        Command line editor, prompt routines, new glob syntax and numerous
        fixes and speedups
      Karl Kleinpaste, CCI 1983-4
        Special aliases, directory stack extraction stuff, login/logout
        watch, scheduled events, and the idea of the new prompt format
      Rayan Zachariassen, University of Toronto, 1984
        ls-F and which builtins and numerous bug fixes, modifications and
        speedups
      Chris Kingsley, Caltech
        Fast storage allocator routines
      Chris Grevstad, TRW, 1987
        Incorporated 4.3BSD csh into tcsh
      Christos S. Zoulas, Cornell U. EE Dept., 1987-94
        Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c,



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        SHORT_STRINGS support and a new version of sh.glob.c
      James J Dempsey, BBN, and Paul Placeway, OSU, 1988
        A/UX port
      Daniel Long, NNSC, 1988
        wordchars
      Patrick Wolfe, Kuck and Associates, Inc., 1988
        vi mode cleanup
      David C Lawrence, Rensselaer Polytechnic Institute, 1989
        autolist and ambiguous completion listing
      Alec Wolman, DEC, 1989
        Newlines in the prompt
      Matt Landau, BBN, 1989
        ~/.tcshrc
      Ray Moody, Purdue Physics, 1989
        Magic space bar history expansion
      Mordechai ????, Intel, 1989
        printprompt() fixes and additions
      Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
        Automatic spelling correction and prompt3
      Per Hedeland, Ellemtel, Sweden, 1990-
        Various bugfixes, improvements and manual updates
      Hans J. Albertsson (Sun Sweden)
        ampm, settc and telltc
      Michael Bloom
        Interrupt handling fixes
      Michael Fine, Digital Equipment Corp
        Extended key support
      Eric Schnoebelen, Convex, 1990
        Convex support, lots of csh bug fixes, save and restore of directory
        stack
      Ron Flax, Apple, 1990
        A/UX 2.0 (re)port
      Dan Oscarsson, LTH Sweden, 1990
        NLS support and simulated NLS support for non NLS sites, fixes
      Johan Widen, SICS Sweden, 1990
        shlvl, Mach support, correct-line, 8-bit printing
      Matt Day, Sanyo Icon, 1990
        POSIX termio support, SysV limit fixes
      Jaap Vermeulen, Sequent, 1990-91
        Vi mode fixes, expand-line, window change fixes, Symmetry port
      Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
        autolist beeping options, modified the history search to search for
        the whole string from the beginning of the line to the cursor.
      Scott Krotz, Motorola, 1991
        Minix port
      David Dawes, Sydney U. Australia, Physics Dept., 1991
        SVR4 job control fixes
      Jose Sousa, Interactive Systems Corp., 1991
        Extended vi fixes and vi delete command
      Marc Horowitz, MIT, 1991
        ANSIfication fixes, new exec hashing code, imake fixes, where



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      Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
        ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
        and various other portability changes and bug fixes
      Jeff Fink, 1992
        complete-word-fwd and complete-word-back
      Harry C. Pulley, 1992
        Coherent port
      Andy Phillips, Mullard Space Science Lab U.K., 1992
        VMS-POSIX port
      Beto Appleton, IBM Corp., 1992
        Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
        SIGHUP
      Scott Bolte, Cray Computer Corp., 1992
        CSOS port
      Kaveh R. Ghazi, Rutgers University, 1992
        Tek, m88k, Titan and Masscomp ports and fixes.  Added autoconf
        support.
      Mark Linderman, Cornell University, 1992
        OS/2 port
      Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
        Linux port
      Tim P. Starrin, NASA Langley Research Center Operations, 1993
        Read-only variables
      Dave Schweisguth, Yale University, 1993-4
        New man page and tcsh.man2html
      Larry Schwimmer, Stanford University, 1993
        AFS and HESIOD patches
      Luke Mewburn, RMIT University, 1994-6
        Enhanced directory printing in prompt, added ellipsis and rprompt.
      Edward Hutchins, Silicon Graphics Inc., 1996
        Added implicit cd.
      Martin Kraemer, 1997
        Ported to Siemens Nixdorf EBCDIC machine
      Amol Deshpande, Microsoft, 1997
        Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
        library and message catalog code to interface to Windows.
      Taga Nayuta, 1998
        Color ls additions.

 THANKS TO
      Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve
      Romig, Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky
      and all the other people at Ohio State for suggestions and
      encouragement

      All the people on the net, for putting up with, reporting bugs in, and
      suggesting new additions to each and every version

      Richard M. Alderson III, for writing the `T in tcsh' section





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