XVI(1) Unix XVI(1)
2.50
NAME
xvi - multi-file text editor
SYNOPSIS
xvi { -R } { -c command } { -s parameter-assignment } [ -t tag |
+number | +/pattern ] { filename ... }
DESCRIPTION
Xvi (pronounced ecks-vee-eye) is a free, portable, multi-window
implementation of the popular vi(1) editor. It has some useful
enhancements, although, as described below, not all of vi's features
have been implemented yet, and some things work differently from vi.
This manual page describes the differences between xvi and POSIX,
classic vi and other popular vi clones. For a full reference manual,
see the manual page for classic vi under http://ex-vi.sourceforge.net
and the POSIX specifications for ex and vi. For a tutorial, see An
Introduction to Display Editing with Vi.
OPTIONS
The following command-line options are available:
-R Start the editor in read-only mode.
-c command
Execute command as an ex command in the first buffer after
reading input files or going to a tag. Multiple -c flags are
allowed.
-s parameter-assignment
Set the value of the specified parameter at startup. The
assignment has the same form as when given as an editor command,
i.e:
name=string
for string parameters
name=number
for numeric parameters
name to turn a Boolean parameter on
noname
to turn a Boolean parameter off Parameters set with -s take
their new values before opening input files or going to a
tag.
-t tag
Edit the file containing the definition specified as tag, at the
start of the definition (as per vi).
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+number
Go to the specified line number of the file being edited.
+$ goes to the last line,
+-number
goes to the nth line before the last line and
+- goes to the penultimate line.
+/pattern
Go to the first occurrence of the specified pattern within the
file being edited. The -l, -L, -r, -V command line options are
not supported and -wn is ignored.
ENHANCEMENTS
Parameter handling
Xvi supports 5 types of parameter: as well as vi's numeric, string and
boolean, it also has enumerated and list types. The former is used
for format, infoupdate, jumpscroll, preserve and regextype, while the
latter is currently only used for tags. The advantage of the
enumerated type is that if you try to set an illegal value, the set of
correct values will be displayed, which is very useful if you have
forgotten what the values may be. (Try :set preserve to see an
example of this.) Like the : commands and parameter names, an
enumerated value can also be set by giving enough of its initial
characters to uniquely identify it.
Multiple buffers and windows
Xvi supports multiple buffers and windows. A buffer is the internal
object which holds a file in memory, while a window is an area of the
screen which shows part of a buffer. Every window references a
buffer, even if no file is being edited. The following commands are
available for operating on buffers and windows:
:buffer
create a new buffer in a new window; can be followed by a
filename, which will be edited in the new buffer.
:close
close the current window; will also close the buffer if this is
the last window on to it.
:equalise
make all windows as nearly the same size as possible.
:split
create a new window on to the current buffer by splitting the
current window in half. The two resulting windows are similar to
viewports on to a single editing buffer, in that changes made in
one window are reflected in the other one.
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:x / ZZ
close only the current window. If the window is the only one on
to the buffer, the buffer will be closed as well, writing it
first if it is modified.
g move to the next window.
^W increase the size of the current window (may be given a numeric
prefix, default is one line).
^T decrease the size of the current window (may be given a numeric
prefix, default is one line).
^O make the current window as large as possible.
^] as for vi, but create a new buffer window if appropriate (and if
autosplit allows). Note that the :quit command quits out of the
editor, not out of a window. The :close command is thus the
equivalent of :quit for windows. There is no equivalent of :x or
ZZ for the whole editor; these have been hijacked for operations
on windows. The boolean autosplit parameter specifies whether of
buffer windows that will be created automatically whenever you
either edit more than one file, or use tags to edit a different
file. The minrows parameter specifies the minimum number of rows
to which a window may be shrunk, including the status line. The
default value is 2; 0 and 1 may also be useful. Undo works per
buffer, as do marks; yank/put and redo (the . command) work over
all buffers, i.e. you can delete from one buffer and put the text
into a different buffer.
Named buffers
As well as the normal named (conjugate) buffers, and the default one
named @, several extra buffers named :, /, ?, ! and < contain the last
command lines entered for each of the four command types and for the
last thing inserted. So, for instance, @: will re-execute the last
colon command, or you can insert it into your buffer, edit it and then
re-execute it (e.g. with dd@@).
Function keys
For keyboards with function keys, F1 displays a page of help, while F2
to F10 produce #2 to #9 and #0, which you can :map! or :map to phrases
that you type often or to useful command sequences.
File preservation
Rather than use vi's Unix-specific method for preservation, xvi does
periodic preservation of all files currently being edited into
temporary files in the same directory. It tries to do this when you
aren't typing, so that you won't notice the short delay when the
temporary file is written out. Obviously, only changed files are
preserved in this way, and the temporary file is removed once the real
file has been successfully written. As an additional safety measure,
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when a file is explicitly saved and it appears not to have been
preserved recently, it is normally preserved first. This ensures
that, even if the operating system crashes while the real file is
being created, there should always be at least one recent copy of it
in the filesystem. The :preserve command is available as in vi to
preserve a specific buffer manually. The level of safety provided by
the preservation facility may be configured by changing the values of
the preserve and preservetime parameters. The following values are
available for preserve:
unsafe
Never preserve any buffer before an explicit save. This can be
useful on old, slow, floppy-only systems, but is not generally
recommended.
standard
The default value. Only preserve a buffer before an explicit
save if it appears not to have been preserved recently.
safe Always preserve buffers before they are written.
paranoid
As for safe, but the preserve file is never removed, even after
the file has been successfully written. In all cases, all
modified buffers are preserved automatically after no user events
have been received for preservetime seconds, if a minimum number
of events (currently 60) have been received since the last
automatic preservation. This behaviour can be more or less
disabled by setting preservetime to a very high value. The names
given to preserve files are system-dependent, but are generally
of the form ``filename.tmp'', or ``filename.001'' to
``filename.999''. If a preserve file already exists, it will not
be overwritten; instead, a new filename will be generated.
8-bit character support
Characters with the top bit set may be displayed, although it is not
yet possible to have null ('\0') bytes in a file buffer. How the
characters are displayed varies between systems; on UNIX, they will be
shown as an octal escape sequence, while on MS-DOS, OS/2 and QNX they
will be shown as the actual character in the PC character set. This
can be controlled by setting the cchars and mchars variables; if these
parameters are set, control- and meta-characters (respectively) are
shown directly, otherwise they are shown as some sequence of printable
characters. Tabs are normally displayed as a series of spaces of the
appropriate length (according to the tabstops parameter); setting list
mode will cause them to be displayed as control characters, as will
unsetting the tabs parameter. How the tab character is displayed is
then under the control of the cchars parameter. You can use the ^_
(control-underscore) command to flip the top bit of the character the
cursor is on. This may be useful on systems where it is otherwise
impossible to enter 8-bit characters.
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File formats
Xvi can read and write text files in non-Unix formats. The current
format is given by the value of the format parameter, which may be set
to "unix", "msdos", and so on. This means you can edit MS-DOS files
under UNIX, etc. To see a list of available formats, type
:se fmt=? If the new boolean autodetect parameter is set, xvi
sniffs files before reading them to determine their newline style
and sets the default file-saving newline style to that of the
file read. It would be better if the file format were remembered
separately for each file but instead it is a single editor-wide
option that applies to all open buffers. The same could be said
for the "readonly" option.
Extended regular expressions
vi's magic parameter is superseded by the regextype parameter, which
can take the following values:
tags only ^ and $ are significant (used for tags)
grep like grep(1), but with \< and \> added
egrep
like egrep(1), but with \< and \> added The default is grep.
Note that it is still possible to set or unset magic as in vi;
this will simply result in regextype being set as appropriate.
The sections and paragraphs parameters define egrep-style
patterns to search for, rather than vi's simplistic (and troff-
dependent) character pairs. A similar parameter, sentences,
defines a pattern for the ( and ) motions.
Improved replace mode
The R command acts more intelligently when you press return - it
leaves the rest of the current line alone, and just starts replacing
text on the next line, starting at the screen column where you first
typed R.
Command line editing and filename completion
While entering a `:' command or a `/' search string, as well as the
usual keys, Backspace to cancel the previous character, ^W to cancel
the previous word and ^U to cancel the line, xvi also lets you move
back and forth in the line with the arrow keys to correct typing
errors. For file-oriented commands, the Tab key performs filename
completion on the last word of the line, which can be the first part
of a file's name or a filename regular expressions containing special
characters ?, * and maybe others, depending on your operating system.
Command re-execution
As well as the normal named (conjugate) buffers, and the default one
(named @), there exist several extra ones named :, /, ? and !, which
contain the last command lines typed to each of the given commands.
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So for instance, @: will re-execute the last ex command, or you can
insert it into your buffer, edit it and then re-execute it (e.g. with
dd@@).
Scrolling
When multiple windows are used, xvi normally has to be able to scroll
individual windows without scrolling the whole screen. This can be
very inefficient on terminals without scrolling regions, so the
jumpscroll parameter is provided to control the editor's scrolling
behaviour. It can be set to one of:
off When the cursor moves outside a window's boundaries, and the new
position is near enough, the window will scroll to the new
position.
on When the cursor moves outside a window's boundaries, the window
will always jump to the new position.
auto A window will scroll only if it can do so efficiently; otherwise
it will jump. The default value is auto. On ISA-type systems
which have memory-mapped displays, hardware character generators
and reasonably fast processors, jumpscroll should generally be
set to off; however, on LCD screens or other displays with a long
image persistence, this may actually make the text more difficult
to read, and many users may be more comfortable with it turned
on. Explicit scroll commands (e.g. ^D and ^E) are not affected
by the jumpscroll parameter.
Colour
There are four new parameters to control screen colours:
colour
colour used for text
statuscolour
colour used for status lines
roscolour
as statuscolour, but for read-only files
systemcolour
colour used for system mode (i.e. subshells and after
termination) These parameters are numeric, and the value means
different things on different operating systems. On Unix, it is
an index into the termcap(5) entries "c0" to "c9", which are
assumed to be colour-setting escape sequences if they are
present. If they are not present, "so" (begin standout mode) and
"se" (end standout mode) are used instead. Values of 0 and 1
give normal text, whereas 2 and above give standout mode. The
default colour for the roscolour parameter will generally involve
red if colours are available; this is intended to provide a
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warning to the user that writing the file may not be possible.
On-line help
A primitive help facility is available; the :help command simply
creates a new buffer window on to a standard help file. The name of
the file which is edited is given by the helpfile string parameter;
the default on Unix versions is "/usr/lib/xvi.help". Note that the
help file buffer will be marked "not editable" when it is created,
which prevents accidental overwriting of the help file even when the
file permissions would allow it.
Mouse support
Some mouse support is available for micro-based systems and
workstations Clicking the mouse button on:
any line outside current window
changes current window to the one indicated by the mouse (can be
used instead of g).
top line of any window
scrolls window downwards (same as ^Y).
bottom line of any window
scrolls window upwards (same as ^E).
status line of any window
shows current file and lines (same as ^G).
any text line of any window
moves text cursor as near as possible to mouse cursor. Also,
windows can be resized by dragging the appropriate status line up
or down with the mouse.
Miscellaneous
The command :wn (write file and edit next) is provided, as in PC-vi.
In insert and replace modes, ^A has the same meaning as ^@ in vi,
except that it works at any time, not just for the first character.
Also, typing ^Bx where x is the name of a conjugate buffer, inserts
the contents of that buffer into the input stream at that point. A
new parameter infoupdate (iu for short), when set to continuous shows
the current line number on the status line as you move in the file.
Its default value of terse just shows the filename. When the boolean
parameter tabindent is clear (:set notabindent), automatic indentation
does not use tab characters and is done with spaces.
LIMITATIONS
Ex mode
The main area in which xvi is lacking is vi's ex mode, which is not
implemented at all (and neither are edit, e, or open modes). However,
many of the ex commands are available in vi mode as colon commands;
the colon commands that have not been implemented are mostly those
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which offer the same functionality as other commands in vi mode. In
particular, abbreviate, append, change, ex, insert, open, recover,
unabbreviate, write>>, z and | have not been implemented as colon
commands yet.
Vi mode
The Q command is inappropriate in the context of xvi, since there is
no ex mode.
Parameters
The following parameters have not been implemented, and probably won't
be:
ada(vim), adapath(vim), autoprint, directory, edcompatible,
hardtabs, lisp, mesg, modelines, open, optimize, prompt, redraw,
slowopen, sourceany, term, terse, ttytype, window
The command :se all gives a complete list, with current values, of
those that have been.
Miscellaneous
It is not possible to interrupt the editor while it is performing
certain operations. If you start off a big global command, you have
to wait for it to finish. Flags and counts after ex mode commands are
not supported. The :substitute command does not support splitting of
lines. Regular expressions, although implemented (see above), do not
support the ~ metacharacter on the left hand side. The :global
command only supports the commands [lps&~d]. Undo does not work
properly when applied to macros (either @ or :map); it should undo all
the changes made by the macro, but in fact only the last command
within the macro is undone.
OTHER DIFFERENCES FROM VI
The XVINIT environment variable is read instead of EXINIT. Whilst no
files are sourced automatically, users who wish to have a startup file
can arrange it very easily. sh(1) or ksh(1) users should add this
line to their $HOME/.profile:
XVINIT='source xvi-startup-file'; export XVINIT csh(1) users
should add this to their $HOME/.login:
setenv XVINIT 'source xvi-startup-file' and MS-DOS users should
add this to their autoexec.bat:
set XVINIT=sourcexvi-startup-file The tags parameter can be used
to specify multiple tags files; these can be separated by either
``\ '' (backslash space) or ``,'' (comma). Alternate files are
handled slightly differently, owing to the presence of buffer and
window handling. Essentially, when you close a buffer, its
filename is remembered as the alternate file; when you invoke the
^^ or :e # commands, this file is re-edited. Note that ^^ edits
the alternate file in a new buffer window, if autosplit allows.
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FILES
/usr/lib/xvi.helpDefault help file.
SEE ALSO
ex(1), vi(1), termcap(5).
BUGS
See also http://github.com/martinwguy/xvi/issues
+ Most termcap(5) terminal descriptions are only tested with vi(1)
(and possibly rogue(6)). Since xvi is, in some ways, more
demanding than vi in its use of termcap capabilities, it
sometimes exposes bugs or inadequacies in termcap entries. This
applies especially to scrolling regions.
AVAILABILITY
Xvi has been ported to MS-DOS, OS/2, QNX, Atari ST, Amiga and many
different versions of Unix. Downloads are available under
http://xvi.sf.net and the source code is maintained at
http://github.com/martinwguy/xvi
AUTHORS
Chris and John Downey. Derived from STEVIE, written by Tim Thompson
and Tony Andrews.
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