LESSKEY(1) General Commands Manual LESSKEY(1)
[1mNAME[0m
lesskey - customize key bindings for less
[1mSYNOPSIS (deprecated)[0m
[1mlesskey [-o output] [--] [input][0m
[1mlesskey [--output=output] [--] [input][0m
[1mlesskey -V[0m
[1mlesskey --version[0m
[1mSCOPE[0m
This document describes the format of the [1mlesskey [22msource file, which is
used by [1mless [22mversion 582 and later. In previous versions of [1mless[22m, a
separate program called [1mlesskey [22mwas used to compile the [1mlesskey [22msource
file into a format understood by [1mless[22m. This compilation step is no
longer required and the [1mlesskey [22mprogram is therefore deprecated, al‐
though the file format remains supported by [1mless [22mitself.
[1mDESCRIPTION[0m
A [1mlesskey [22mfile specifies a set of key bindings and environment vari‐
ables to be used by subsequent invocations of [1mless[22m.
[1mFILE FORMAT[0m
The input file consists of one or more [4msections[24m. Each section starts
with a line that identifies the type of section. Possible sections
are:
#command
Customizes command key bindings.
#line-edit
Customizes line-editing key bindings.
#env Defines environment variables.
Blank lines and lines which start with a hash mark (#) are ignored, ex‐
cept as noted below.
[1mCOMMAND SECTION[0m
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:
[4mstring[24m <whitespace> [4maction[24m [extra-string] <newline>
Whitespace is any sequence of one or more spaces and/or tabs. The
[4mstring[24m is the command key(s) which invoke the action. The [4mstring[24m may
be a single command key, or a sequence of up to 15 keys. The [4maction[24m is
the name of the less action, from the list below. The characters in
the [4mstring[24m 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 fol‐
lowed by certain characters specifies input characters as follows:
\b BACKSPACE (0x08)
\e ESCAPE (0x1B)
\n NEWLINE (0x0A)
\r RETURN (0x0D)
\t TAB (0x09)
\k followed by a single character represents the char(s) produced
when one of these keys is pressed:
\kb BACKSPACE (the BACKSPACE key)
\kB ctrl-BACKSPACE
\kd DOWN ARROW
\kD PAGE DOWN
\ke END
\kh HOME
\ki INSERT
\kl LEFT ARROW
\kL ctrl-LEFT ARROW
\kr RIGHT ARROW
\kR ctrl-RIGHT ARROW
\kt BACKTAB
\ku UP ARROW
\kU PAGE UP
\kx DELETE
\kX ctrl-DELETE
\k1 F1
A backslash followed by any other character indicates that charac‐
ter is to be taken literally. Characters which must be preceded
by backslash include caret, space, tab, hash mark and the back‐
slash itself.
An action may be followed by an "extra" string. When such a com‐
mand is entered while running [1mless[22m, the action is performed, and
then the extra string is parsed, just as if it were typed in to
[1mless[22m. 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 [1mless [22mquits, the first charac‐
ter of the extra string is used as its exit status.
[1mEXAMPLE[0m
The following input file describes the set of default command keys used
by [1mless[22m. Documentation on each command can be found in the man page,
under the key sequence which invokes the command.
#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
\eF forw-until-hilite
R repaint-flush
r repaint
^R repaint
^L repaint
\eu undo-hilite
\eU clear-search
g goto-line
\kh goto-line
< goto-line
\e< goto-line
p percent
% percent
\e[ left-scroll
\e] right-scroll
\e( left-scroll
\e) right-scroll
\kl left-scroll
\kr right-scroll
\e{ no-scroll
\e} end-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
\ke goto-end
\eG goto-end-buffered
= 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
& filter
m set-mark
M set-mark-bottom
\em clear-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
## Use a long option name by starting the
## extra string with ONE dash; eg:
## s toggle-option -log-file\n
_ display-option
| pipe
v visual
! shell
# pshell
+ 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
[1mPRECEDENCE[0m
Commands specified by [1mlesskey [22mtake precedence over the default com‐
mands. A default command key may be disabled by including it in the
input file with the action "invalid". Alternatively, a key may be de‐
fined to do nothing by using the action "noaction". "noaction" is sim‐
ilar to "invalid", but [1mless [22mwill 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.
[1mLINE EDITING SECTION[0m
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.
[1mEXAMPLE[0m
The following input file describes the set of default line-editing keys
used by [1mless[22m:
#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
^G abort
[1mLESS ENVIRONMENT VARIABLES[0m
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 [1mless[22m. If a variable is specified in the
system environment and also in a lesskey file, the value in the lesskey
file takes precedence.
If the variable name is followed by += rather than =, the string is ap‐
pended to the variable's existing value. This currently works only if
any += lines immediately follow the same variable's original definition
(with an = line), without any intervening definitions of other vari‐
ables. It can append only to a variable defined earlier in the file;
it cannot append to a variable in the system environment. The string
is appended literally, without any extra whitespace added, so if white‐
space is desired, it should be appended to the end of the preceding
line. (It cannot be added to the beginning of the += string because
space after the equals sign is ignored, as noted above.)
[1mCONDITIONAL CONFIGURATION[0m
If a line begins with #version followed by a relational operator and a
version number, the remainder of the line is parsed if and only if the
running version of [1mless [22m(or [1mlesskey[22m) matches the operator. This can be
helpful if a lesskey file is used by different versions of [1mless[22m.
For example, suppose that a new command named 'sideways-search' is
added in [1mless [22mversion 777. Then the following line would assign the
command to the Q key, but only in versions of [1mless [22mwhich support it.
The line would be ignored by versions earlier than 777.
#version >= 777 Q sideways-search
These six operators are supported:
> Greater than
< Less than
>= Greater than or equal to
<= Less than or equal to
= Equal to
!= Not equal to
The #version feature is not supported in [1mless [22mand [1mlesskey [22mbefore ver‐
sion 594. In those older versions, all #version lines are ignored.
[1mEXAMPLE[0m
The following input file sets the -i and -S options when is run and, on
version 595 and higher, adds a --color option.
#env
## (Note that there must be a space at the end of the next line,
## to separate the --color option from the -S option.)
LESS = -i -S
#version >= 595 LESS += --color=Hkc
[1mSEE ALSO[0m
[1mless[22m(1)
[1mWARNINGS[0m
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 \340 in a lesskey file.
[1mCOPYRIGHT[0m
Copyright (C) 1984-2023 Mark Nudelman
less is part of the GNU project and is free software. You can redis‐
tribute it and/or modify it under the terms of either (1) the GNU Gen‐
eral Public License as published by the Free Software Foundation; or
(2) the Less License. See the file README in the less distribution for
more details regarding redistribution. You should have received a copy
of the GNU General Public License along with the source for less; see
the file COPYING. If not, write to the Free Software Foundation, 59
Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also
have received a copy of the Less License; see the file LICENSE.
less is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT‐
NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
more details.
[1mAUTHOR[0m
Mark Nudelman
Report bugs at
https://github.com/gwsw/less/issues.
Version 643: 20 Jul 2023 LESSKEY(1)
