remove unused global db environment

[nvi.git] / docs / vi.ref / set.opt.texi

@comment  Copyright (c) 1994
@comment      The Regents of the University of California.  All rights reserved.
@comment  Copyright (c) 1994, 1995, 1996
@comment        Keith Bostic.  All rights reserved.
@comment 
@comment  See the LICENSE file for redistribution information.
@comment 
@comment      $Id: set.opt.texi,v 8.1 2001/08/18 20:43:48 skimo Exp $ (Berkeley) $Date: 2001/08/18 20:43:48 $
@comment 
@chapter Set Options

There are a large number of options that may be set (or unset) to
change the editor's behavior.
This section describes the options, their abbreviations and their
default values.

In each entry below, the first part of the tag line is the full name
of the option, followed by any equivalent abbreviations.
(Regardless of the abbreviations, it is only necessary to use the
minimum number of characters necessary to distinguish an abbreviation
from all other commands for it to be accepted, in
@EV{nex,nvi}.
Historically, only the full name and the official abbreviations
were accepted by
@EV{ex,vi}.
Using full names in your startup files and environmental variables will
probably make them more portable.)
The part in square brackets is the default value of the option.
Most of the options are boolean, i.e. they are either on or off,
and do not have an associated value.

Options apply to both
@CO{ex}
and
@CO{vi}
modes, unless otherwise specified.

With a few exceptions,
all options are settable per screen, i.e. the
@OP{tags}
option can be set differently in each screen.
The exceptions are the
@OP{columns},
@OP{lines},
@OP{secure}
and
@OP{term}
options.
Changing these options modifies the respective information for all screens.

For information on modifying the options or to display the options and
their current values, see the
@QQ{set}
command in the section entitled
@QB{Ex Commands} .
@itemize @bullet
@cindex altwerase
@IP{altwerase [off]}

@CO{Vi}
only.
Change how
@CO{vi}
does word erase during text input.
When this option is set, text is broken up into three classes:
alphabetic, numeric and underscore characters, other nonblank
characters, and blank characters.
Changing from one class to another marks the end of a word.
In addition, the class of the first character erased is ignored
(which is exactly what you want when erasing pathname components).
@cindex autoindent
@IP{autoindent, ai [off]}

If this option is set, whenever you create a new line (using the
@CO{vi}
@CO{A},
@CO{a},
@CO{C},
@CO{c},
@CO{I},
@CO{i},
@CO{O},
@CO{o},
@CO{R},
@CO{r},
@CO{S},
and
@CO{s}
commands, or the
@CO{ex}
@CO{append},
@CO{change},
and
@CO{insert}
commands) the new line is automatically indented to align the cursor with
the first nonblank character of the line from which you created it.
Lines are indented using tab characters to the extent possible (based on
the value of the
@OP{tabstop}
option) and then using space characters as necessary.
For commands inserting text into the middle of a line, any blank characters
to the right of the cursor are discarded, and the first nonblank character
to the right of the cursor is aligned as described above.
@sp 1
The indent characters are themselves somewhat special.
If you do not enter more characters on the new line before moving to
another line, or entering
@LI{<escape>},
the indent character will be deleted and the line will be empty.
For example, if you enter
@LI{<carriage-return>}twice in succession,
the line created by the first
@LI{<carriage-return>}will not have any characters in it,
regardless of the indentation of the previous or subsequent line.
@sp 1
Indent characters also require that you enter additional erase characters
to delete them.
For example,
if you have an indented line, containing only blanks, the first
@LI{<word-erase>}character you enter will erase up to end of the indent characters,
and the second will erase back to the beginning of the line.
(Historically, only the
@LI{<control-D>}key would erase the indent characters.
Both the
@LI{<control-D>}key and the usual erase keys work in
@CO{nvi}.)
In addition, if the cursor is positioned at the end of the indent
characters, the keys
@QT{0<control-D>}
will erase all of the indent characters for the current line,
resetting the indentation level to 0.
Similarly, the keys
@QT{^<control-D>}
will erase all of the indent characters for the current line,
leaving the indentation level for future created lines unaffected.
@sp 1
Finally, if the
@OP{autoindent}
option is set, the
@CO{S}
and
@CO{cc}
commands change from the first nonblank of the line to the end of the
line, instead of from the beginning of the line to the end of the line.
@cindex autoprint
@IP{autoprint, ap [off]}

@CO{Ex}
only.
Cause the current line to be automatically displayed after the
@CO{ex}
commands
@CO{<},
@CO{>},
@CO{copy},
@CO{delete},
@CO{join},
@CO{move},
@CO{put},
@CO{t},
@CO{Undo},
and
@CO{undo}.
This automatic display is suppressed during
@CO{global}
and
@CO{v}
commands, and for any command where optional flags are used to explicitly
display the line.
@cindex autowrite
@IP{autowrite, aw [off]}

If this option is set, the
@CO{vi}
@CO{!},
@CO{^^},
@CO{^]}
and
@CO{<control-Z>}
commands, and the
@CO{ex}
@CO{edit},
@CO{next},
@CO{rewind},
@CO{stop},
@CO{suspend},
@CO{tag},
@CO{tagpop},
and
@CO{tagtop}
commands automatically write the current file back to the current file name
if it has been modified since it was last written.
If the write fails, the command fails and goes no further.
@sp 1
Appending the optional force flag character
@QT{!}
to the
@CO{ex}
commands
@CO{next},
@CO{rewind},
@CO{stop},
@CO{suspend},
@CO{tag},
@CO{tagpop},
and
@CO{tagtop}
stops the automatic write from being attempted.
@sp 1
(Historically, the
@CO{next}
command ignored the optional force flag.)
Note, the
@CO{ex}
commands
@CO{edit},
@CO{quit},
@CO{shell},
and
@CO{xit}
are
@emph{not}
affected by the
@OP{autowrite}
option.
@sp 1
The
@OP{autowrite}
option is ignored if the file is considered read-only for any reason.
@comment  I cannot get a double quote to print between the square brackets
@comment  to save my life.  The ONLY way I've been able to get this to work
@comment  is with the .tr command.
@cindex backup
@IP{backup [""]}

If this option is set, it specifies a pathname used as a backup file,
and, whenever a file is written, the file's current contents are copied
to it.
The pathname is
@QT{#},
@QT{%}
and
@QT{!}
expanded.
@sp 1
If the first character of the pathname is
@QT{N},
a version number is appended to the pathname (and the
@QT{N}
character is then discarded).
Version numbers are always incremented, and each backup file will have
a version number one greater than the highest version number currently
found in the directory.
@sp 1
Backup files must be regular files, owned by the real user ID of the
user running the editor, and not accessible by any other user.
@cindex beautify
@IP{beautify, bf [off]}

If this option is set, all control characters that are not currently being
specially interpreted, other than
@LI{<tab>},
@LI{<newline>},
and
@LI{<form-feed>},
are
discarded from commands read in by
@CO{ex}
from command files, and from input text entered to
@CO{vi}
(either into the file or to the colon command line).
Text files read by
@EV{ex,vi}
are
@emph{not}
affected by the
@OP{beautify}
option.
@cindex cdpath
@IP{cdpath [environment variable CDPATH, or current directory]}

This option is used to specify a colon separated list of directories
which are used as path prefixes for any relative path names used as
arguments for the
@CO{cd}
command.
The value of this option defaults to the value of the environmental
variable
@LI{CDPATH}if it is set, otherwise to the current directory.
For compatibility with the POSIX 1003.2 shell, the
@CO{cd}
command does
@emph{not}
check the current directory as a path prefix for relative path names
unless it is explicitly specified.
It may be so specified by entering an empty string or a
@QT{.}
character into the
@LI{CDPATH}variable or the option value.
@cindex cedit
@IP{cedit [no default]}

This option adds the ability to edit the colon command-line history.
This option is set to a string.
Whenever the first character of that string is entered on the colon
command line,
you will enter a normal editing window on the collected commands that
you've entered on the
@CO{vi}
colon command-line.
You may then modify and/or execute the commands.
All normal text editing is available,
except that you cannot use
@CO{<control-W>}
to switch to an alternate screen.
Entering a
@CO{<carriage-return>}
will execute the current line of the screen window as an ex command in
the context of the screen from which you created the colon command-line
screen,
and you will then return to that screen.
@sp 1
Because of
@CO{vi}'s
parsing rules, it can be difficult to set the colon command-line edit
character to the
@LI{<escape>}character.
To set it to
@LI{<escape>},
use
@QT{set cedit=<literal-next><escape>}.
@sp 1
If the
@OP{cedit}
edit option is set to the same character as the
@OP{filec}
edit option,
@CO{vi}
will perform colon command-line editing if the character is entered as
the first character of the line,
otherwise,
@CO{vi}
will perform file name expansion.
@cindex columns
@IP{columns, co [80]}

The number of columns in the screen.
Setting this option causes
@EV{ex,vi}
to set (or reset) the environmental variable
@LI{COLUMNS}.
See the section entitled
@QB{Sizing the Screen}
more information.
@cindex comment
@IP{comment [off]}

@CO{Vi}
only.
If the first non-empty line of the file begins with the string
@QT{#},
@QT{/*}
or
@QT{//},
this option causes
@CO{vi}
to skip to the end of that shell, C or C++ comment (probably a
terribly boring legal notice) before displaying the file.
@cindex directory
@IP{directory, dir [environment variable TMPDIR, or /tmp]}

The directory where temporary files are created.
The environmental variable
@LI{TMPDIR}is used as the default value if it exists, otherwise
@LI{/tmp}is used.
@cindex edcompatible
@IP{edcompatible, ed [off]}

Remember the values of the
@QQ{c}
and
@QQ{g}
suffixes to the
@CO{substitute}
commands, instead of initializing them as unset for each new
command.
Specifying pattern and replacement strings to the
@CO{substitute}
command unsets the
@QQ{c}
and
@QQ{g}
suffixes as well.
@cindex escapetime
@IP{escapetime [1]}

The 10th's of a second
@EV{ex,vi}
waits for a subsequent key to complete an
@LI{<escape>}key mapping.
@cindex errorbells
@IP{errorbells, eb [off]}

@CO{Ex}
only.
@CO{Ex}
error messages are normally presented in inverse video.
If that is not possible for the terminal, setting this option causes
error messages to be announced by ringing the terminal bell.
@cindex exrc
@IP{exrc, ex [off]}

If this option is turned on in the EXINIT environment variables,
or the system or $HOME startup files,
the local startup files are read,
unless they are the same as the system or $HOME startup files or
fail to pass the standard permission checks.
See the section entitled
@QB{Startup Information}
for more information.
@cindex extended
@IP{extended [off]}

This option causes all regular expressions to be treated as POSIX
1003.2 Extended Regular Expressions (which are similar to historic
@XR{egrep,1}
style expressions).
@cindex filec
@IP{filec [no default]}

This option adds the ability to do shell expansion when entering input
on the colon command line.
This option is set to a string.
Whenever the first character of that string is entered on the colon
command line,
the <blank> delimited string immediately before the cursor is expanded
as if it were followed by a
@LI{*}character, and file name expansion for the
@CO{ex}
edit command was done.
If no match is found, the screen is flashed and text input resumed.
If a single match results, that match replaces the expanded text.
In addition, if the single match is for a directory, a
@LI{/}character is appended and file completion is repeated.
If more than a single match results,
any unique prefix shared by the matches replaces the expanded text,
the matches are displayed,
and text input resumed.
@sp 1
Because of
@CO{vi}'s
parsing rules, it can be difficult to set the path completion character
to two command values,
@LI{<escape>}and
@LI{<tab>}.
To set it to
@LI{<escape>},
use
@QT{set filec=<literal-next><escape>}.
To set it to
@LI{<tab>},
use
@QT{set filec=\e<tab>}.
@sp 1
If the
@OP{cedit}
edit option is set to the same character as the
@OP{filec}
edit option,
@CO{vi}
will perform colon command-line editing if the character is entered as
the first character of the line,
otherwise,
@CO{vi}
will perform file name expansion.
@cindex flash
@IP{flash [on]}

This option causes the screen to flash instead of beeping the keyboard,
on error, if the terminal has the capability.
@cindex hardtabs
@IP{hardtabs, ht [8]}

This option defines the spacing between hardware tab settings, i.e.
the tab expansion done by the operating system and/or the terminal
itself.
As
@EV{nex,nvi}
never writes
@LI{<tab>}characters to the terminal, unlike historic versions of
@EV{ex,vi},
this option does not currently have any affect.
@cindex iclower
@IP{iclower [off]}

The
@OP{iclower}
edit option makes all Regular Expressions case-insensitive,
as long as an upper-case letter does not appear in the search string.
@cindex ignorecase
@IP{ignorecase, ic [off]}

This option causes regular expressions, both in
@CO{ex}
commands and in searches,
to be evaluated in a case-insensitive manner.
@cindex keytime
@IP{keytime [6]}

The 10th's of a second
@EV{ex,vi}
waits for a subsequent key to complete a key mapping.
@cindex leftright
@IP{leftright [off]}

@CO{Vi}
only.
This option causes the screen to be scrolled left-right to view
lines longer than the screen, instead of the traditional
@CO{vi}
screen interface which folds long lines at the right-hand margin
of the terminal.
@cindex lines
@IP{lines, li [24]}

@CO{Vi}
only.
The number of lines in the screen.
Setting this option causes
@EV{ex,vi}
to set (or reset) the environmental variable
@LI{LINES}.
See the section entitled
@QB{Sizing the Screen}
for more information.
@cindex lisp
@IP{lisp [off]}

@CO{Vi}
only.
This option changes the behavior of the
@CO{vi}
@CO{(},
@CO{)},
@strong{@{},
@strong{@}},
@CO{[[}
and
@CO{]]}
commands to match the Lisp language.
Also, the
@OP{autoindent}
option's behavior is changed to be appropriate for Lisp.
@sp 1
@emph{This option is not yet implemented.}
@cindex list
@IP{list [off]}

This option causes lines to be displayed in an unambiguous fashion.
Specifically, tabs are displayed as control characters, i.e.
@QT{^I},
and the ends of lines are marked with a
@QT{$}
character.
@cindex lock
@IP{lock [on]}

This option causes the editor to attempt to get an exclusive lock on
any file being edited, read or written.
Reading or writing a file that cannot be locked produces a warning
message, but no other effect.
Editing a file that cannot be locked results in a read only edit session,
as if the
@OP{readonly}
edit option were set.
@cindex magic
@IP{magic [on]}

This option is on by default.
Turning the
@OP{magic}
option off causes all regular expression characters except for
@QT{^}
and
@QT{$},
to be treated as ordinary characters.
To re-enable characters individually, when the
@OP{magic}
option is off,
precede them with a backslash
@QT{\e}
character.
See the section entitled
@QB{Regular Expressions and Replacement Strings}
for more information.
@cindex matchtime
@IP{matchtime [7]}

@CO{Vi}
only.
The 10th's of a second
@CO{vi}
pauses on the matching character when the
@OP{showmatch}
option is set.
@cindex mesg
@IP{mesg [on]}

This option allows other users to contact you using the
@XR{talk,1}
and
@XR{write,1}
utilities, while you are editing.
@EV{Ex,vi}
does not turn message on, i.e. if messages were turned off when the
editor was invoked, they will stay turned off.
This option only permits you to disallow messages for the edit session.
See the
@XR{mesg,1}
utility for more information.
@cindex msgcat
@IP{msgcat [./]}

This option selects a message catalog to be used to display error and
informational messages in a specified language.
If the value of this option ends with a '/', it is treated as the name
of a directory that contains a message catalog
@QT{vi_XXXX},
where
@QT{XXXX}
is the value of the
@LI{LANG}environmental variable, if it's set, or the value of the
@LI{LC_MESSAGES}environmental variable if it's not.
If neither of those environmental variables are set,
or if the option doesn't end in a '/',
the option is treated as the full path name of the message catalog to use.
@sp 1
If any messages are missing from the catalog,
the backup text (English) is used instead.
@sp 1
See the distribution file
@LI{catalog/README}for additional information on building and installing message catalogs.
@cindex modelines
@IP{modelines, modeline [off]}

If the
@OP{modelines}
option is set,
@EV{ex,vi}
has historically scanned the first and last five lines of each file as
it is read for editing, looking for any
@CO{ex}
commands that have been placed in those lines.
After the startup information has been processed, and before the user
starts editing the file, any commands embedded in the file are executed.
@sp 1
Commands were recognized by the letters
@QQ{e}
or
@QQ{v}
followed by
@QQ{x}
or
@QQ{i},
at the beginning of a line or following a tab or space character,
and followed by a
@QQ{:},
an
@CO{ex}
command, and another
@QQ{:}.
@sp 1
This option is a security problem of immense proportions,
and should not be used under any circumstances.
@sp 1
@emph{This option will never be implemented.}
@comment  I cannot get a double quote to print between the square brackets
@comment  to save my life.  The ONLY way I've been able to get this to work
@comment  is with the .tr command.
@cindex noprint
@IP{noprint [""]}

Characters that are never handled as printable characters.
By default, the C library function
@XR{isprint,3}
is used to determine if a character is printable or not.
This edit option overrides that decision.
@cindex number
@IP{number, nu [off]}

Precede each line displayed with its current line number.
@cindex octal
@IP{octal [off]}

Display unknown characters as octal numbers
@PQ{"\e###"},
instead of the default
hexadecimal
@PQ{"\ex##"}.
@cindex open
@IP{open [on]}

@CO{Ex}
only.
If this option is not set, the
@CO{open}
and
@CO{visual}
commands are disallowed.
@cindex optimize
@IP{optimize, opt [on]}

@CO{Vi}
only.
Throughput of text is expedited by setting the terminal not to do automatic
carriage returns when printing more than one (logical) line of output,
greatly speeding output on terminals without addressable cursors when text
with leading white space is printed.
@sp 1
@emph{This option is not yet implemented.}
@cindex paragraphs
@IP{paragraphs, para [IPLPPPQPP LIpplpipbp]}

@CO{Vi}
only.
Define additional paragraph boundaries for the
@CO{@{}
and
@strong{@}}
commands.
The value of this option must be a character string consisting
of zero or more character pairs.
@sp 1
In the text to be edited, the character string
@LI{<newline>.<char-pair>},
(where
@LI{<char-pair>}is one of the character pairs in the option's value)
defines a paragraph boundary.
For example, if the option were set to
@LI{LaA<space>##},
then all of the following additional paragraph boundaries would be
recognized:
@sp 1
@example
<newline>.La
<newline>.A<space>
<newline>.##
@end example
@cindex path
@IP{path []}

The path option can be used to specify a <colon>-separated list of
paths, similar to the
@LI{PATH}environment variable in the shells.
If this option is set,
the name of the file to be edited is not an absolute pathname,
the first component of the filename is not
@QT{.}
or
@QT{..},
and the file to be edited doesn't exist in the current directory,
the elements of the
@OP{path}
option are sequentially searched for a file of the specified name.
If such a file is found, it is edited.
@comment  I cannot get a double quote to print between the square brackets
@comment  to save my life.  The ONLY way I've been able to get this to work
@comment  is with the .tr command.
@cindex print
@IP{print [""]}

Characters that are always handled as printable characters.
By default, the C library function
@XR{isprint,3}
is used to determine if a character is printable or not.
This edit option overrides that decision.
@cindex prompt
@IP{prompt [on]}

@CO{Ex}
only.
This option causes
@CO{ex}
to prompt for command input with a
@QT{:}
character; when it is not set, no prompt is displayed.
@cindex readonly
@IP{readonly, ro [off]}

This option causes a force flag to be required to attempt to write the file.
Setting this option is equivalent to using the
@strong{-R}
command line option,
or executing the
@CO{vi}
program using the name
@CO{view}.
@sp 1
The
@OP{readonly}
edit option is not usually persistent, like other edit options.
If the
@strong{-R}
command line option is set,
@CO{vi}
is executed as
@CO{view},
or the
@OP{readonly}
edit option is explicitly set,
all files edited in the screen will be marked readonly,
and the force flag will be required to write them.
However, if none of these conditions are true,
or the
@OP{readonly}
edit option is explicitly unset,
then the
@OP{readonly}
edit option will toggle based on the write permissions of the file currently
being edited as of when it is loaded into the edit buffer.
In other words, the
@OP{readonly}
edit option will be set if the current file lacks write permissions,
and will not be set if the user has write permissions for the file.
@cindex recdir
@IP{recdir [/var/tmp/vi.recover]}

The directory where recovery files are stored.
@sp 1
If you change the value of
@OP{recdir},
be careful to choose a directory whose contents are not regularly
deleted.
Bad choices include directories in memory based filesystems,
or
@LI{/tmp},
on most systems,
as their contents are removed when the machine is rebooted.
@sp 1
Public directories like
@LI{/usr/tmp}and
@LI{/var/tmp}are usually safe, although some sites periodically prune old files
from them.
There is no requirement that you use a public directory,
e.g. a sub-directory of your home directory will work fine.
@sp 1
Finally, if you change the value of
@OP{recdir},
you must modify the recovery script to operate in your chosen recovery
area.
@sp 1
See the section entitled
@QB{Recovery}
for further information.
@cindex redraw
@IP{redraw, re [off]}

@CO{Vi}
only.
The editor simulates (using great amounts of output), an intelligent
terminal on a dumb terminal (e.g. during insertions in
@CO{vi}
the characters to the right of the cursor are refreshed as each input
character is typed).
@sp 1
@emph{This option is not yet implemented.}
@cindex remap
@IP{remap [on]}

If this option is set,
it is possible to define macros in terms of other macros.
Otherwise, each key is only remapped up to one time.
For example, if
@QT{A}
is mapped to
@QT{B},
and
@QT{B}
is mapped to
@QT{C},
The keystroke
@QT{A}
will be mapped to
@QT{C}
if the
@OP{remap}
option is set, and to
@QT{B}
if it is not set.
@cindex report
@IP{report [5]}

Set the threshold of the number of lines that need to be changed or
yanked before a message will be displayed to the user.
For everything but the yank command, the value is the largest value
about which the editor is silent, i.e. by default, 6 lines must be
deleted before the user is notified.
However, if the number of lines yanked is greater than
@emph{or equal to}
the set value, it is reported to the user.
@cindex ruler
@IP{ruler [off]}

@CO{Vi}
only.
Display a row/column ruler on the colon command line.
@cindex scroll
@IP{scroll, scr [(environment variable LINES - 1) / 2]}

Set the number of lines scrolled by the
@CO{ex}
@CO{<control-D>}
and
@CO{<end-of-file>}
commands.
@sp 1
Historically, the
@CO{ex}
@CO{z}
command, when specified without a count, used two times the size of the
scroll value; the POSIX 1003.2 standard specified the window size, which
is a better choice.
@cindex searchincr
@IP{searchincr [off]}

The
@OP{searchincr}
edit option makes the search commands
@CO{/}
and
@CO{?}
incremental, i.e. the screen is updated and the cursor moves to the matching
text as the search pattern is entered.
If the search pattern is not found,
the screen is beeped and the cursor remains on the colon-command line.
Erasing characters from the search pattern backs the cursor up to the
previous matching text.
@cindex sections
@IP{sections, sect [NHSHH HUnhsh]}

@CO{Vi}
only.
Define additional section boundaries for the
@CO{[[}
and
@CO{]]}
commands.
The
@OP{sections}
option should be set to a character string consisting of zero or
more character pairs.
In the text to be edited, the character string
@LI{<newline>.<char-pair>},
(where
@LI{<char-pair>}is one of the character pairs in the option's value),
defines a section boundary in the same manner that
@OP{paragraphs}
option boundaries are defined.
@cindex secure
@IP{secure [off]}

The
@OP{secure}
edit option turns off all access to external programs.
This means that the versions of the
@CO{read}
and
@CO{write}
commands that filter text through other programs,
the
@CO{vi}
@CO{!}
and
@CO{<control-Z>}
commands,
the
@CO{ex}
@CO{!},
@CO{script},
@CO{shell},
@CO{stop}
and
@CO{suspend}
commands and file name expansion will not be permitted.
Once set,
the
@OP{secure}
edit option may not be unset.
@cindex shell
@IP{shell, sh [environment variable SHELL, or /bin/sh]}

Select the shell used by the editor.
The specified path is the pathname of the shell invoked by the
@CO{vi}
@CO{!}
shell escape command and by the
@CO{ex}
@CO{shell}
command.
This program is also used to resolve any shell meta-characters in
@CO{ex}
commands.
@comment  I cannot get a double quote to print between the square brackets
@comment  to save my life.  The ONLY way I've been able to get this to work
@comment  is with the .tr command.
@cindex shellmeta
@comment @IP{shellmeta [~@{[*?@$`'"\e]}
@item @strong{shellmeta [~@{[*?$`'"\]}

The set of characters that
@CO{ex}
checks for when doing file name expansion.
If any of the specified characters are found in the file name arguments
to the
@CO{ex}
commands,
the arguments are expanded using the program defined by the
@OP{shell}
option.
The default set of characters is a union of meta characters
from the Version 7 and the Berkeley C shell.
@cindex shiftwidth
@IP{shiftwidth, sw [8]}

Set the autoindent and shift command indentation width.
This width is used by the
@OP{autoindent}
option and by the
@CO{<},
@CO{>},
and
@CO{shift}
commands.
@cindex showmatch
@IP{showmatch, sm [off]}

@CO{Vi}
only.
This option causes
@CO{vi},
when a
@comment QT
``@code{@}}''
or
@QT{)}
is entered, to briefly move the cursor the matching
@comment QT
``@code{@{}''
or
@QT{(}.
See the
@OP{matchtime}
option for more information.
@cindex showmode
@IP{showmode, smd [off]}

@CO{Vi}
only.
This option causes
@CO{vi}
to display a string identifying the current editor mode on the colon
command line.
The string is preceded by an asterisk (``*'') if the file has been
modified since it was last completely written,
@cindex sidescroll
@IP{sidescroll [16]}

@CO{Vi}
only.
Sets the number of columns that are shifted to the left or right,
when
@CO{vi}
is doing left-right scrolling and the left or right margin is
crossed.
See the
@OP{leftright}
option for more information.
@cindex slowopen
@IP{slowopen, slow [off]}

This option affects the display algorithm used by
@CO{vi},
holding off display updating during input of new text to improve
throughput when the terminal in use is slow and unintelligent.
@sp 1
@emph{This option is not yet implemented.}
@cindex sourceany
@IP{sourceany [off]}

If this option is turned on,
@CO{vi}
historically read startup files that were owned by someone other than
the editor user.
See the section entitled
@QB{Startup Information}
for more information.
This option is a security problem of immense proportions,
and should not be used under any circumstances.
@sp 1
@emph{This option will never be implemented.}
@cindex tabstop
@IP{tabstop, ts [8]}

This option sets tab widths for the editor display.
@cindex taglength
@IP{taglength, tl [0]}

This option sets the maximum number of characters that are considered
significant in a tag name.
Setting the value to 0 makes all of the characters in the tag name
significant.
@cindex tags
@IP{tags, tag [tags /var/db/libc.tags /sys/kern/tags]}

Sets the list of tags files, in search order,
which are used when the editor searches for a tag.
@cindex term
@IP{term, ttytype, tty [environment variable TERM]}

Set the terminal type.
Setting this option causes
@EV{ex,vi}
to set (or reset) the environmental variable
@LI{TERM}.
@cindex terse
@IP{terse [off]}

This option has historically made editor messages less verbose.
It has no effect in this implementation.
See the
@OP{verbose}
option for more information.
@cindex tildeop
@IP{tildeop [off]}

Modify the
@CO{~}
command to take an associated motion.
@cindex timeout
@IP{timeout, to [on]}

If this option is set,
@EV{ex,vi}
waits for a specific period for a subsequent key to complete a key
mapping (see the
@OP{keytime}
option).
If the option is not set, the editor waits until enough keys are
entered to resolve the ambiguity, regardless of how long it takes.
@cindex ttywerase
@IP{ttywerase [off]}

@CO{Vi}
only.
This option changes how
@CO{vi}
does word erase during text input.
If this option is set, text is broken up into two classes,
blank characters and nonblank characters.
Changing from one class to another marks the end of a word.
@cindex verbose
@IP{verbose [off]}

@CO{Vi}
only.
@CO{Vi}
historically bells the terminal for many obvious mistakes, e.g. trying
to move past the left-hand margin, or past the end of the file.
If this option is set, an error message is displayed for all errors.
@cindex w300
@IP{w300 [no default]}

@CO{Vi}
only.
Set the window size if the baud rate is less than 1200 baud.
See the
@OP{window}
option for more information.
@cindex w1200
@IP{w1200 [no default]}

@CO{Vi}
only.
Set the window size if the baud rate is equal to 1200 baud.
See the
@OP{window}
option for more information.
@cindex w9600
@IP{w9600 [no default]}

@CO{Vi}
only.
Set the window size if the baud rate is greater than 1200 baud.
See the
@OP{window}
option for more information.
@cindex warn
@IP{warn [on]}

@CO{Ex}
only.
This option causes a warning message to the terminal if the file has
been modified, since it was last written, before a
@CO{!}
command.
@cindex window
@IP{window, w, wi [environment variable LINES - 1]}

This option determines the default number of lines in a screenful,
as displayed by the
@CO{z}
command.
It also determines the number of lines scrolled by the
@CO{vi}
commands
@CO{<control-B>}
and
@CO{<control-F>},
and the default number of lines scrolled by the
@CO{vi}
commands
@CO{<control-D>}
and
@CO{<control-U>}.
The value of window can be unrelated to the real screen size,
although it starts out as the number of lines on the screen.
See the section entitled
@QB{Sizing the Screen}
for more information.
Setting the value of the
@OP{window}
option is the same as using the
@strong{-w}
command line option.
@sp 1
If the value of the
@OP{window}
option (as set by the
@OP{window},
@OP{w300},
@OP{w1200}
or
@OP{w9600}
options) is smaller than the actual size of the screen,
large screen movements will result in displaying only that smaller
number of lines on the screen.
(Further movements in that same area will result in the screen being
filled.)
This can provide a performance improvement when viewing different
places in one or more files over a slow link.
@sp 1
Resetting the window size does not reset the default number of lines
scrolled by the
@CO{<control-D>}
and
@CO{<control-U>}
commands.
@cindex windowname
@IP{windowname [off]}

@CO{Vi}
changes the name of the editor's icon/window to the current file name
when it's possible and not destructive, i.e.,
when the editor can restore it to its original value on exit or when
the icon/window will be discarded as the editor exits.
If the
@OP{windowname}
edit option is set,
@CO{vi}
will change the icon/window name even when it's destructive and the
icon/window name will remain after the editor exits.
(This is the case for
@XR{xterm,1}).
@cindex wraplen
@IP{wraplen, wl [0]}

This option is identical to the
@OP{wrapmargin}
option, with the exception that it specifies the number of columns
from the
@emph{left}
margin before the line splits, not the right margin.
@sp 1
If both
@OP{wraplen}
and
@OP{wrapmargin}
are set, the
@OP{wrapmargin}
value is used.
@cindex wrapmargin
@IP{wrapmargin, wm [0]}

@CO{Vi}
only.
If the value of the
@OP{wrapmargin}
option is non-zero,
@CO{vi}
will split lines so that they end at least that number of columns
before the right-hand margin of the screen.
(Note, the value of
@OP{wrapmargin}
is
@emph{not}
a text length.
In a screen that is 80 columns wide, the command
@QT{:set wrapmargin=8}
attempts to keep the lines less than or equal to 72 columns wide.)
@sp 1
Lines are split at the previous whitespace character closest to the
number.
Any trailing whitespace characters before that character are deleted.
If the line is split because of an inserted
@LI{<space>}or
@LI{<tab>}character, and you then enter another
@LI{<space>}character, it is discarded.
@sp 1
If wrapmargin is set to 0,
or if there is no blank character upon which to split the line,
the line is not broken.
@sp 1
If both
@OP{wraplen}
and
@OP{wrapmargin}
are set, the
@OP{wrapmargin}
value is used.
@cindex wrapscan
@IP{wrapscan, ws [on]}

This option causes searches to wrap around the end or the beginning
of the file, and back to the starting point.
Otherwise, the end or beginning of the file terminates the search.
@cindex writeany
@IP{writeany, wa [off]}

If this option is set, file-overwriting checks that would usually be
made before the
@CO{write}
and
@CO{xit}
commands, or before an automatic write (see the
@OP{autowrite}
option), are not made.
This allows a write to any file, provided the file permissions allow it.
@end itemize