lesskey(F)

lesskey -- file format for less command key bindings

Format

#section
value description

Description

The lesskey file is an input text file specifying the set of key bindings to be used by the less(C) command. The lesskey(C) command creates an output binary file from this text file that is read when less is invoked.

If no input file is specified, the default $HOME/.lesskey file is used. If the input file is "-", standard input is read.

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, the default $HOME/.less file is used. 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. Valid 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.

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 more 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.

CAUTION: Use the #stop line carefully. 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 difficulties executing necessary commands.

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:

\b: BACKSPACE
\e: ESCAPE
\n: NEWLINE
\r: RETURN
\t: TAB
\ku: UP ARROW
\kd: DOWN ARROW
\kr: RIGHT ARROW
\kl: LEFT ARROW
\kU: PAGE UP
\kD: PAGE DOWN
\kh: HOME
\ke: END
\kx: 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 more, the action is performed, and then the extra string is parsed, just as if it were typed in to more. 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 more quits, the first character of the extra string is used as its exit status.

NOTE: It is not possible to specify special keys, such as up-arrow, in a keyboard-independent manner. The only way to specify such keys is to specify the escape sequence which a particular keyboard sends when such a keys is pressed.

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

#command
\r: forw-line
\n: forw-line
e: forw-line
j: forw-line
\kd: 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
\40: forw-screen
f: forw-screen
^F: forw-screen
^V: forw-screen
\kD: forw-screen
b: back-screen
^B: back-screen
\ev: back-screen
\kU: back-screen
z: forw-window
w: back-window
\e\40: forw-screen-force
F: forw-forever
R: repaint-flush
r: repaint
^R: repaint
^L: repaint
\eu: undo-hilite
g: goto-line
<: goto-line
\e<: goto-line
p: percent
%: percent
\e[: left-scroll
\e]: right-scroll
\e(: left-scroll
\e): right-scroll
{: forw-bracket {}
}: back-bracket {}
(: forw-bracket ()
): back-bracket ()
[: forw-bracket []
]: back-bracket []
\e^F: forw-bracket
\e^B: back-bracket
G: goto-end
\e>: goto-end
>: goto-end
=: status
^G: status
:f: status
/: forw-search
?: back-search
\e/: forw-search *
\e?: back-search *
n: repeat-search
\en: repeat-search-all
N: reverse-search
\eN: reverse-search-all
m: set-mark
': goto-mark
^X^X: goto-mark
E: examine
:e: examine
^X^V: examine
:n: next-file
:p: prev-file
:x: index-file
-: toggle-option
:t: toggle-option t
:o: 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

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.

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

#line-edit
\t: forw-complete
\17: back-complete
\e\t: back-complete
^L: expand
^V: literal
^A: literal
\el: right
\kr: right
\eh: left
\kl: left
\eb: word-left
\e\kl: word-left
\ew: word-right
\e\kr: word-right
\ei: insert
\ex: delete
\kx: delete
\eX: word-delete
\ekx: word-delete
\e\b: word-backspace
\e0: home
\kh: home
\e$: end
\ke: end
\ek: up
\ku: up
\ej: down

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 equal sign (=) and the value to be assigned to the environment variable. White space before and after the equal sign is ignored. Variables assigned in this way are visible only to more. 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 more configuration information stored in one file.

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

#env
MORE = -i
LESSCHARSET = latin1

Files

$HOME/.lesskey: input text file
$HOME/.less: output binary file generated by lesskey(C)