## NAME

lesskey - specify key bindings for less

## SYNOPSIS

lesskey [-o output] [--] [input]
lesskey [--output=output] [--] [input]
lesskey -V
lesskey --version

## DESCRIPTION

Lesskey is used to specify a set of key bindings to be used by less. The input file is a text file which describes the key bindings. If the input file is "-", standard input is read. If no input file is specified, a standard filename is used as the name of the input file, which depends on the system being used: On Unix systems, $HOME/.lesskey is used; on MS-DOS systems, $HOME/_lesskey is used; and on OS/2 systems $HOME/lesskey.ini is used, or $INIT/lesskey.ini if $HOME is undefined. The output file is a binary file which is used by less. If no output file is specified, and the environment variable LESSKEY is set, the value of LESSKEY is used as the name of the output file. Otherwise, a standard filename is used as the name of the output file, which depends on the system being used: On Unix and OS-9 systems, $HOME/.less is used; on MS-DOS systems, $HOME/_less is used; and on OS/2 systems, $HOME/less.ini is used, or $INIT/less.ini if $HOME is undefined. If the output file already exists, lesskey will overwrite it.

The -V or --version option causes lesskey to print its version number and immediately exit. If -V or --version is present, other options and arguments are ignored.

The input file consists of one or more sections. Each section starts with a line that identifies the type of section. Possible sections are:

#command

Defines new command keys.

#line-edit

Defines new line-editing keys.

#env

Defines environment variables.

Blank lines and lines which start with a pound sign (#) are ignored, except for the special section header lines.

## COMMAND SECTION

The command section begins with the line

#command

If the command section is the first section in the file, this line may be omitted. The command section consists of lines of the form:

string <whitespace> action [extra-string] <newline>

Whitespace is any sequence of one or more spaces and/or tabs. The string is the command key(s) which invoke the action. The string may be a single command key, or a sequence of up to 15 keys. The action is the name of the less action, from the list below. The characters in the string may appear literally, or be prefixed by a caret to indicate a control key. A backslash followed by one to three octal digits may be used to specify a character by its octal value. A backslash followed by certain characters specifies input characters as follows:

\eb

BACKSPACE

\ee

ESCAPE

\en

NEWLINE

\er

RETURN

\et

TAB

\eku

UP ARROW

\ekd

DOWN ARROW

\ekr

RIGHT ARROW

\ekl

LEFT ARROW

\ekU

PAGE UP

\ekD

PAGE DOWN

\ekh

HOME

\eke

END

\ekx

DELETE

A backslash followed by any other character indicates that character is to be taken literally. Characters which must be preceded by backslash include caret, space, tab and the backslash itself.

An action may be followed by an "extra" string. When such a command is entered while running less, the action is performed, and then the extra string is parsed, just as if it were typed in to less. This feature can be used in certain cases to extend the functionality of a command. For example, see the "{" and ":t" commands in the example below. The extra string has a special meaning for the "quit" action: when less quits, first character of the extra string is used as its exit status.

## EXAMPLE

The following input file describes the set of default command keys used by less:

    	#command
    	er		forw-line
    	en		forw-line
    	e		forw-line
    	j		forw-line
    	ekd	forw-line
    	^E		forw-line
    	^N		forw-line
    	k		back-line
    	y		back-line
    	^Y		back-line
    	^K		back-line
    	^P		back-line
    	J		forw-line-force
    	K		back-line-force
    	Y		back-line-force
    	d		forw-scroll
    	^D		forw-scroll
    	u		back-scroll
    	^U		back-scroll
    	e40	forw-screen
    	f		forw-screen
    	^F		forw-screen
    	^V		forw-screen
    	ekD	forw-screen
    	b		back-screen
    	^B		back-screen
    	eev		back-screen
    	ekU	back-screen
    	z		forw-window
    	w		back-window
    	eee40		forw-screen-force
    	F		forw-forever
    	eeF		forw-until-hilite
    	R		repaint-flush
    	r		repaint
    	^R		repaint
    	^L		repaint
    	eeu		undo-hilite
    	g		goto-line
    	ekh	goto-line
    	<		goto-line
    	ee<		goto-line
    	p		percent
    	%		percent
    	ee[		left-scroll
    	ee]		right-scroll
    	ee(		left-scroll
    	ee)		right-scroll
    	{		forw-bracket {}
    	}		back-bracket {}
    	(		forw-bracket ()
    	)		back-bracket ()
    	[		forw-bracket []
    	]		back-bracket []
    	ee^F		forw-bracket
    	ee^B		back-bracket
    	G		goto-end
    	ee>		goto-end
    	>		goto-end
    	eke	goto-end
    	=		status
    	^G		status
    	:f		status
    	/		forw-search
    	?		back-search
    	ee/		forw-search *
    	ee?		back-search *
    	n		repeat-search
    	een		repeat-search-all
    	N		reverse-search
    	eeN		reverse-search-all
    	&		filter
    	m		set-mark
    	'		goto-mark
    	^X^X		goto-mark
    	E		examine
    	:e		examine
    	^X^V		examine
    	:n		next-file
    	:p		prev-file
    	t		next-tag
    	T		prev-tag
    	:x		index-file
    	:d		remove-file
    	-		toggle-option
    	:t		toggle-option t
    	s		toggle-option o
    	_		display-option
    	|		pipe
    	v		visual
    	!		shell
    	+		firstcmd
    	H		help
    	h		help
    	V		version
    	0		digit
    	1		digit
    	2		digit
    	3		digit
    	4		digit
    	5		digit
    	6		digit
    	7		digit
    	8		digit
    	9		digit
    	q		quit
    	Q		quit
    	:q		quit
    	:Q		quit
    	ZZ		quit

## PRECEDENCE

Commands specified by lesskey take precedence over the default commands. A default command key may be disabled by including it in the input file with the action "invalid". Alternatively, a key may be defined to do nothing by using the action "noaction". "noaction" is similar to "invalid", but less will give an error beep for an "invalid" command, but not for a "noaction" command. In addition, ALL default commands may be disabled by adding this control line to the input file:

#stop

This will cause all default commands to be ignored. The #stop line should be the last line in that section of the file.

Be aware that #stop can be dangerous. Since all default commands are disabled, you must provide sufficient commands before the #stop line to enable all necessary actions. For example, failure to provide a "quit" command can lead to frustration.

## LINE EDITING SECTION

The line-editing section begins with the line:

#line-edit

This section specifies new key bindings for the line editing commands, in a manner similar to the way key bindings for ordinary commands are specified in the #command section. The line-editing section consists of a list of keys and actions, one per line as in the example below.

## EXAMPLE

The following input file describes the set of default line-editing keys used by less:

    	#line-edit
    	et	    	forw-complete
    	e17		back-complete
    	eeet		back-complete
    	^L		expand
    	^V		literal
    	^A		literal
       	eel		right
    	ekr		right
    	eeh		left
    	ekl		left
    	eeb		word-left
    	eeekl	word-left
    	eew		word-right
    	eeekr	word-right
    	eei		insert
    	eex		delete
    	ekx		delete
    	eeX		word-delete
    	eekx		word-delete
    	eeeb		word-backspace
    	ee0		home
    	ekh		home
    	ee$		end
    	eke		end
    	eek		up
    	eku		up
    	eej		down
    	^G		abort

## LESS ENVIRONMENT VARIABLES

The environment variable section begins with the line

#env

Following this line is a list of environment variable assignments. Each line consists of an environment variable name, an equals sign (=) and the value to be assigned to the environment variable. White space before and after the equals sign is ignored. Variables assigned in this way are visible only to less. If a variable is specified in the system environment and also in a lesskey file, the value in the lesskey file takes precedence. Although the lesskey file can be used to override variables set in the environment, the main purpose of assigning variables in the lesskey file is simply to have all less configuration information stored in one file.

## EXAMPLE

The following input file sets the -i option whenever less is run, and specifies the character set to be "latin1":

    	#env
    	LESS = -i
    	LESSCHARSET = latin1

## SEE ALSO

less(1)

## WARNINGS

On MS-DOS and OS/2 systems, certain keys send a sequence of characters which start with a NUL character (0). This NUL character should be represented as e340 in a lesskey file.

## COPYRIGHT

Copyright (C) 2000-2012 Mark Nudelman

lesskey is part of the GNU project and is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version.

lesskey is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with lesskey; see the file COPYING. If not, write to the Free Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.

## AUTHOR

Mark Nudelman <bug-less@gnu.org>
Send bug reports or comments to bug-less@gnu.org.