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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

      slsh - Interpreter for S-Lang scripts

      slsh [ --help ] [ --version ] [ -g ] [ -n ] [ --init file ] [ --no-
      readline ] [ -e string ] [ -i ] [ -q, --quiet ] [ -t ] [ -v ] [
      -|script-file args... ]

      slsh is a simple program for interpreting S-Lang scripts.  It supports
      dynamic loading of S-Lang modules and includes a readline interface
      for interactive use.

           Show a summary of options

           Show slsh version information

      -g   Compile with debugging code, tracebacks, etc

      -n   Don't load the personal initialization file

      --init file
           Use this file instead of ~/.slshrc

           Do not use a readline interface for the interactive mode

      -e string
           Execute ``string'' as S-Lang code.

      -i   Force interactive mode.  Normally slsh will go into interactive
           mode if both stdin and stdout are attached to a terminal.

      -q, --quiet
           Startup quietly by not printing the version and copyright

      -t   Normally, slsh will call slsh_main if it is defined.  This option
           prevents that from happening making it useful for checking for
           syntax error.

      -v   Show verbose loading messages.  This is useful for seeing what
           files are being loaded.

      Upon startup, the program will try to load slsh.rc as follows. If
      either SLSH_CONF_DIR or SLSH_LIB_DIR environment variables exist, then

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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

      slsh will look look in the corresponding directories for slsh.rc.
      Otherwise it will look in:

      $(prefix)/etc/   (as specified in the Makefile)





      The slsh.rc file may load other files from slsh's library directory in
      the manner described below.

      Once slsh.rc has been loaded, slsh will load $HOME/.slshrc if present.
      Finally, it will load the script specified on the command line.  If
      the name of the script is -, then it will be read from stdin.  If the
      script name is not present, or a string to execute was not specified
      using the -e option, then slsh will go into interactive mode and read
      input from the terminal.  If the script is present and defines a
      function called slsh_main, that function will be called.

      When a script loads a file via the built-in evalfile function or the
      require function (autoloaded by slsh.rc), the file is searched for
      along the SLSH_PATH as specified in the Makefile.  An alternate path
      may be specified by the SLSH_PATH environment variable.

      The search path may be queried and set during run time via the
      get_slang_load_path and set_slang_load_path functions, e.g.,

         set_slang_load_path ("/home/bill/lib/slsh:/usr/share/slsh");

      When slsh is invoked without a script or is given the -i command line
      argument, it will go into into interactive mode.  In this mode, the
      user will be prompted for input.  The program will leave this mode and
      exit if it sees an EOF (Ctrl-D) or the user exits by issuing the quit

      If an uncaught exception occurs during execution of a command, the
      error message will be shown and the user will be prompted for more

      Any objects left on the stack after a command will be printed and the
      stack cleared.  This makes interactive mode useful as a calculator,

           slsh> 3*10;

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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

           slsh> x = [1:20];
           slsh> sum (sin(x)-cos(x));
           slsh> quit;
      Note that in this mode, variables are automatically declared.

      The interactive mode also supports command logging.  Logging is
      enabled by the start_log function.  The stop_log function will turn
      off logging.  The default file where logging information will be
      written is slsh.log.  An alternative may be specified as an optional
      argument to the start_log function:

           slsh> start_log;
           Logging input to slsh.log
           slsh> stop_log;
           slsh> start_log("foo.log");
           Logging input to foo.log
           slsh> stop_log;
           slsh> start_log;
           Logging input to foo.log

      Similarly, the save_input function may be used to save the previous
      input to a specified file:

           slsh> save_input;
           Input saved to slsh.log
           slsh> save_input ("foo.log");
           Input saved to foo.log

      As the above examples indicate, lines must end in a semicolon.  This
      is a basic feature of the language and permits commands to span
      multiple lines, e.g.,

           slsh> x = [
           slsh> sum(x);
      For convenience some users prefer that commands be automatically
      terminated with a semicolon.  To have a semicolon silently appended to
      the end of an input line, put the following in $HOME/.slshrc file:

          #ifdef __INTERACTIVE__
          slsh_append_semicolon (1);

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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

      The interactive mode also supports shell escapes.  To pass a command
      to the shell, prefix it with !, e.g.,

          slsh> !pwd
          slsh> !cd doc/tm
          slsh> !pwd

      Finally, the interactive mode supports a help and apropos function:

          slsh> apropos list
          apropos list ==>
          slsh> help list_append

             Append an object to a list

             list_append (List_Type, object, Int_Type nth)
      For convenience, the help and apropos functions do not require the
      syntactic constraints of the other functions.

      By default, slsh is built to use the S-Lang readline interface, which
      includes a customizable command completion and a history mechanism.
      When slsh (or any S-Lang application that makes use of this feature)
      starts in interactive mode, it will look for a file in the user's home
      directory called .slrlinerc and load it if present.  This file allows
      the user to customize the readline interface and enable the history to
      be saved between sessions.  As an example, here is a version of the
      author's .slrlinerc file:

           % Load some basic functions that implement the history mechanism
           () = evalfile ("rline/slrline.rc");
           % The name of the history file -- expands to .slsh_hist for slsh
           RLine_History_File = "$HOME/.${name}_hist";

           % Some addition keybindings.  Some of these functions are defined
           % in rline/, loaded by rline/slrline.rc
           rline_unsetkey ("^K");
           rline_setkey ("bol",   "^B");
           rline_setkey ("eol",   "^E");

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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

           rline_setkey (&rline_kill_eol,  "^L");
           rline_setkey (&rline_set_mark,  "^K^B");
           rline_setkey (&rline_copy_region, "^Kk");
           rline_setkey (&rline_kill_region, "^K^V");
           rline_setkey (&rline_yank,  "^K^P");
           rline_setkey ("redraw",   "^R");

           #ifexists rline_up_hist_search
           % Map the up/down arrow to the history search mechanism
           rline_setkey (&rline_up_hist_search, "\e[A");
           rline_setkey (&rline_down_hist_search, "\e[B");

           #ifexists rline_edit_history
           rline_setkey (&rline_edit_history, "^Kj");

           % Add a new function
           private define double_line ()
              variable p = rline_get_point ();
              variable line = rline_get_line ();
              rline_eol ();
              variable pend = rline_get_point ();
              rline_ins (line);
              rline_set_point (pend + p);
          rline_setkey (&double_line,  "^K^L");

      Several useful example scripts are located in
      $prefix/share/slsh/scripts/, where $prefix represents the slsh
      installation prefix (/usr, /usr/local,...).  These scripts include:

      sldb A script that runs the S-Lang debugger.

           Reports the size of a jpeg file.

           A shell for browsing an SVN repository.

      The principal author of slsh is John E. Davis <>.  The
      interactive mode was provided by Mike Noble.  The S-Lang library upon
      which slsh is based is primarily the work of John E. Davis with help
      from many others.

      This manual page was originally written by Rafael Laboissiere for the
      Debian system (but may be used by others).

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 SLSH(1)                                                             SLSH(1)
                                28 March 2011

      Permission is granted to copy, distribute and/or modify this document
      under the terms of the GNU General Public License, Version 2 any later
      version published by the Free Software Foundation.

      On Debian systems, the complete text of the GNU General Public License
      can be found in /usr/share/common-licenses/GPL

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