1 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 Historically, only the full name and the official abbreviations were accepted by 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 and modes, unless otherwise specified. For information on modifying the options or to display the options and their current values, see the command in the section entitled

altwerase [off]
    only. Change how 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).

autoindent, ai [off]
    If this option is set, whenever you create a new line (using the and commands, or the and 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 [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.

    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 the indent character will be deleted and the line will be empty. For example, if you enter twice in succession, the line created by the first will not have any characters in it, regardless of the indentation of the previous or subsequent line.

    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 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 key would erase the indent characters. Both the key and the usual erase keys work in In addition, if the cursor is positioned at the end of the indent characters, the keys will erase all of the indent characters for the current line, resetting the indentation level to 0. Similarly, the keys will erase all of the indent characters for the current line, leaving the indentation level for future created lines unaffected.

    Finally, if the [autoindent] option is set, the and 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.

autoprint, ap [off]
    only. Cause the current line to be automatically displayed after the commands and This automatic display is suppressed during and commands, and for any command where optional flags are used to explicitly display the line.

autowrite, aw [off]
    If this option is set, the and commands, and the and 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.

    Appending the optional force flag character to the commands and stops the automatic write from being attempted.

    (Historically, the command ignored the optional force flag.) Note, the commands and are affected by the [autowrite] option.

beautify, bf [off]
    If this option is set, all control characters that are not currently being specially interpreted, other than and are discarded from commands read in by from command files, and from input text entered to (either into the file or to the colon command line). Text files read by are affected by the [beautify] option.

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 command. The value of this option defaults to the value of the environmental variable if it is set, otherwise to the current directory. For compatibility with the POSIX 1003.2 shell, the command does 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 character into the variable or the option value.

columns, co [80]
    The number of columns in the screen. Setting this option causes to set (or reset) the environmental variable See the section entitled more information.

comment [off]
    only. If the first non-empty line of the file begins with the string this option causes to skip to the end of that C-language comment (probably a terribly boring legal notice) before displaying the file.

directory, dir [environment variable TMPDIR, or /tmp]
    The directory where temporary files are created. The environmental variable is used as the default value if it exists, otherwise is used.

edcompatible, ed [off]
    Remember the values of the and suffices to the commands, instead of initializing them as unset for each new command. Specifying pattern and replacement strings to the command unsets the and suffices as well.

errorbells, eb [off]
    only. 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.

exrc, ex [off]
    If this option is turned off in the system or $HOME startup files, the local startup files are never read (unless they are the same as the system or $HOME startup files). Turning it on has no effect, i.e. the normal checks for local startup files are performed, regardless. See the section entitled for more information.

extended [off]
    This option causes all regular expressions to be treated as POSIX 1003.2 Extended Regular Expressions (which are similar to historic style expressions).

flash [on]
    This option causes the screen to flash instead of beeping the keyboard, on error, if the terminal has the capability.

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 never writes characters to the terminal, unlike historic versions of this option does not currently have any affect.

ignorecase, ic [off]
    This option causes regular expressions, both in commands and in searches, to be evaluated in a case-insensitive manner.

keytime [6]
    The 10th's of a second waits for a subsequent key to complete a key mapping.

leftright [off]
    only. This option causes the screen to be scrolled left-right to view lines longer than the screen, instead of the traditional screen interface which folds long lines at the right-hand margin of the terminal.

lines, li [24]
    only. The number of lines in the screen. Setting this option causes to set (or reset) the environmental variable See the section entitled for more information.

lisp [off]
    only. This option changes the behavior of the and commands to match the Lisp language. Also, the [autoindent] option's behavior is changed to be appropriate for Lisp.

list [off]
    This option causes lines to be displayed in an unambiguous fashion. Specifically, tabs are displayed as control characters, i.e. and the ends of lines are marked with a character.

magic [on]
    This option is on by default. Turning the [magic] option off causes all regular expression characters except for and to be treated as ordinary characters. To re-enable characters individually, when the [magic] option is off, precede them with a backslash character. See the section entitled for more information.

matchtime [7]
    only. The 10th's of a second pauses on the matching character when the [showmatch] option is set.

mesg [on]
    This option allows other users to contact you using the and utilities, while you are editing. 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 utility for more information.

modelines, modeline [off]
    If the [modelines] option is set, has historically scanned the first and last five lines of each file as it is read for editing, looking for any 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.

    Commands were recognized by the letters or followed by or at the beginning of a line or following a tab or space character, and followed by a an command, and another

    This option is a security problem of immense proportions, and should not be used under any circumstances.

number, nu [off]
    Precede each line displayed with its current line number.

octal [off]
    Display unknown characters as octal numbers, instead of the default hexadecimal.

open [on]
    only. If this option is not set, the and commands are disallowed.

optimize, opt [on]
    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.

paragraphs, para [IPLPPPQPP LIpplpipbp]
    only. Define additional paragraph boundaries for the and commands. The value of this option must be a character string consisting of zero or more character pairs.

    In the text to be edited, the character string (where is one of the character pairs in the option's value) defines a paragraph boundary. For example, if the option were set to then all of the following additional paragraph boundaries would be recognized:

    <newline>.La <newline>.A<space> <newline>.##

prompt [on]
    only. This option causes to prompt for command input with a character; when it is not set, no prompt is displayed.

readonly, ro [off]
    This option causes a force flag to be required to attempt to write the file back to the original file name. Setting this option is equivalent to using the command line option, or editing a file which lacks write permission.

recdir [/var/tmp/vi.recover]
    The directory where recovery files are stored.

    If you change the value of be careful to choose a directory whose contents are not regularly deleted. Bad choices include directories in memory based filesystems, or on most systems, as their contents are removed when the machine is rebooted.

    Public directories like and 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.

    Finally, if you change the value of you must modify the recovery script to operate in your chosen recovery area.

    See the section entitled for further information.

redraw, re [off]
    only. The editor simulates (using great amounts of output), an intelligent terminal on a dumb terminal (e.g. during insertions in the characters to the right of the cursor are refreshed as each input character is typed).

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 is mapped to and is mapped to The keystroke will be mapped to if the [remap] option is set, and to if it is not set.

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 the set value, it is reported to the user.

ruler [off]
    only. Display a row/column ruler on the colon command line.

scroll, scr [window / 2]
    Set the number of lines scrolled by the and commands.

    Historically, the 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.

sections, sect [NHSHH HUnhsh]
    only. Define additional section boundaries for the and commands. The [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 (where is one of the character pairs in the option's value), defines a section boundary in the same manner that [paragraph] option boundaries are defined.

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 shell escape command and by the command. This program is also used to resolve any shell meta-characters in commands.

shiftwidth, sw [8]
    Set the autoindent and shift command indentation width. This width is used by the [autoindent] option and by the and commands.

showdirty [off]
    only. Display an asterisk on the colon command line if the file has been modified.

showmatch, sm [off]
    only. This option causes when a or is entered, to briefly move the cursor the matching or See the [matchtime] option for more information.

showmode [off]
    only. This option causes to display a string identifying the current editor mode on the colon command line.

sidescroll [16]
    only. Sets the number of columns that are shifted to the left or right, when is doing left-right scrolling and the left or right margin is crossed. See the [leftright] option for more information.

slowopen, slow [off]
    This option affects the display algorithm used by holding off display updating during input of new text to improve throughput when the terminal in use is slow and unintelligent.

sourceany [off]
    If this option is turned on, historically read startup files that were owned by someone other than the editor user. See the section entitled for more information. This option is a security problem of immense proportions, and should not be used under any circumstances.

tabstop, ts [8]
    This option sets tab widths for the editor display.

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.

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.

term, ttytype, tty [environment variable TERM]
    Set the terminal type. Setting this option causes to set (or reset) the environmental variable

terse [off]
    This option has historically made editor messages less verbose. It has no effect in this implementation. See the [verbose] option for more information.

tildeop
    Modify the command to take an associated motion.

timeout, to [on]
    If this option is set, waits for a specific period for a subsequent key to complete a key mapping (see the [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.

ttywerase [off]
    only. This option changes how 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.

verbose [off]
    only. 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.

w300 [no default]
    only. Set the window size if the baud rate is less than 1200 baud. See the [window] option for more information.

w1200 [no default]
    only. Set the window size if the baud rate is equal to 1200 baud. See the [window] option for more information.

w9600 [no default]
    only. Set the window size if the baud rate is greater than 1200 baud. See the [window] option for more information.

warn [on]
    only. This option causes a warning message to the terminal if the file has been modified, since it was last written, before a command.

window, w, wi [environment variable LINES]
    This option determines the default number of lines in a screenful, as written by the command. It also determines the number of lines scrolled by the commands and 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 for more information). Setting the value of the [window] option is the same as using the command line option.

    If the value of the [window] option (as set by the [window ,] [w300 ,] [w1200] or [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.

wrapmargin, wm [0]
    only. If the value of the [wrapmargin] option is non-zero, will split lines so that they end at least that number of characters before the right-hand margin of the screen. (Note, the value of [wrapmargin] is a text length. In a screen that is 80 columns wide, the command attempts to keep the lines less than or equal to 72 columns wide.)

    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 or character, and you then enter another character, it is discarded.

    If wrapmargin is set to 0, or if there is no blank character upon which to split the line, the line is not broken.

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.

writeany, wa [off]
    If this option is set, file-overwriting checks that would usually be made before the and commands, or before an automatic write (see the [autowrite] option), are not made. This allows a write to any file, provided the file permissions allow it.