LESSKEY(5)

📦 version 710, in fedora 43, fedora 44, nixpkgs unstable

💖 LESSKEY(5) 💖

okay bestie, gather round — this is the manual for lesskey, the file format that tells less(1) how to behave. It lives in the File Formats Manual section of your man pages (that's the 5, iykyk), and honestly? It's giving "make less yours." 🎀

✨ NAME ✨

lesskey</purl> — customize key bindings for less

🌸 DESCRIPTION 🌸

So here's the tea 🍓: a lesskey file is where you write down a whole set of key bindings and environment variables, and every time you run less(1) after that, it uses them. It's basically a little wardrobe of vibes for your pager.

The input file is made of one or more sections. Each section kicks off with a line that says what kind of section it is. The possible sections are:

#command — customizes your command key bindings. 💅
#line-edit — customizes your line-editing key bindings. ✍️
#env — defines environment variables. 🌈

Blank lines are ignored, periodt. And any text that comes after an unescaped hash mark (#) on a line is ignored too — except in the cases noted further down, so don't get it twisted. 🙈

👑 COMMAND SECTION 👑

The command section starts with this line:

#command

Here's a lil shortcut bestie 🫶: if the command section is the first section in the file, you can just... omit that line. It knows. It's the main character.

The command section is made of lines shaped like this:

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

Whitespace = any sequence of one or more spaces and/or tabs. One or more, be normal about it.
The string is the command key(s) that trigger the action. It can be a single command key, or a sequence of up to 15 keys. Fifteen. That's the ceiling.
The action is the name of the less action — you'll find all of those in the EXAMPLE sections below. 👇

Now for the ✨spicy✨ part — how you write the characters in that string:

You can write the characters literally.
Or prefix one with a caret to mean a control key.
A backslash followed by one to three octal digits specifies a character by its octal value. 🧮
A backslash followed by certain characters specifies input characters like this:

\b   BACKSPACE   (0x08)
\e   ESCAPE      (0x1B)
\n   NEWLINE     (0x0A)
\r   RETURN      (0x0D)
\t   TAB         (0x09)

And then there's the \k girlies — a backslash, k, and then one or two characters, and it represents whatever char(s) get produced when one of these keys gets pressed:

\kb           BACKSPACE (may be different than \b)
\k^b or \kB   ctrl-BACKSPACE
\kd           DOWN ARROW
\k^d          ctrl-DOWN ARROW
\k+d          shift-DOWN ARROW
\kD           PAGE DOWN
\k^D          ctrl-PAGE DOWN
\k+D          shift-PAGE DOWN
\ke           END
\k^e or \kE   ctrl-END
\k+e or \kF   shift-END
\kh           HOME
\k^h or \kH   ctrl-HOME
\k+h or \kI   shift-HOME
\ki           INSERT
\kl           LEFT ARROW
\k^l or \kL   ctrl-LEFT ARROW
\k+l or \kM   shift-LEFT ARROW
\kr           RIGHT ARROW
\k^r or \kR   ctrl-RIGHT ARROW
\k+r or \kS   shift-RIGHT ARROW
\kt           BACKTAB
\ku           UP ARROW
\k^u          ctrl-UP ARROW
\k+u          shift-UP ARROW
\kU           PAGE UP
\k^U          ctrl-PAGE UP
\k+U          shift-PAGE UP
\kx           DELETE
\k^x or \kX   ctrl-DELETE
\k+x          shift-DELETE
\k1           F1
\kp1          lower left key on the numeric keypad
\kp2          lower center key on the numeric keypad
\kp3          lower right key on the numeric keypad
\kp4          center left key on the numeric keypad
\kp5          center key on the numeric keypad
\kp6          center right key on the numeric keypad
\kp7          upper left key on the numeric keypad
\kp8          upper center key on the numeric keypad
\kp9          upper right key on the numeric keypad
\kp0          0 on the numeric keypad
\kp*          * on the numeric keypad
\kp/          / on the numeric keypad
\kp-          - on the numeric keypad
\kp+          + on the numeric keypad
\kp.          . on the numeric keypad
\kp,          , on the numeric keypad
\kpe          ENTER on the numeric keypad

Also, bestie: a backslash followed by any other character means "take that character literally, no thoughts head empty." And these are the characters that must be preceded by a backslash if you want them:

caret ^
space
tab
hash mark #
and the backslash its own self \

💫 The "extra" string (this is the good part) 💫

An action can be followed by an "extra" string. When you type that command while less is running, the action happens, and then the extra string gets parsed — literally just as if you'd typed it straight into less. 😭 It's so cute.

This is how you extend a command's functionality in certain cases — peep the { and :t commands in the example below, they do exactly this. It can also run more than one command on a single keypress. Like, imagine this line was in your lesskey file:

B set-mark b/next\n

Then pressing the B key would first set the b mark, and then search for the string next. Two things, one key. Slay. 💅

⚠️ Important! The extra string means something special for the quit action: when less quits, the ASCII value of the first character of the extra string is used as its exit status. So yeah, plot twist, it's not decorative there. 😳

🦋 EXAMPLE 🦋

The following input file describes the set of default command keys used by less. Documentation on each command lives in the less man page, under the key sequence that invokes the command. Go read that one for the lore. 📖

#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
\ku        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
\eb        back-screen-force
\ej        forw-newline
\ek        back-newline
F          forw-forever
\eF        forw-until-hilite
\ef        forw-bell-hilite
R          repaint-flush
r          repaint
^R         repaint
^L         repaint
\eu        undo-hilite
\eU        clear-search
g          goto-line
\kh        goto-line
\kH        goto-line \e{
\kI        goto-line \e{
\ke        goto-end
\kE        goto-end \e}
\kF        goto-end \e}
<          goto-line
\e<        goto-line
p          percent
%          percent
\e(        left-scroll
\e)        right-scroll
\e]        right-limit-scroll
\e{        no-scroll
\e}        end-scroll
\kl        left-scroll
\kr        right-scroll
\e\kr      right-limit-scroll
\kL        no-scroll
\kM        no-scroll
\kR        end-scroll
\kS        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
P          goto-pos
\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
^O^N       osc8-forw-search
^On        osc8-forw-search
^O^P       osc8-back-search
^Op        osc8-back-search
^O^O       osc8-open
^Oo        osc8-open
^O^L       osc8-jump
^Ol        osc8-jump
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
\e[M       mouse
\e[<       mouse6
\kp1       goto-end
\kp2       forw-line
\kp3       forw-screen
\kp4       left-scroll
\kp6       right-scroll
\kp7       goto-line
\kp8       back-line
\kp9       back-screen
\kp0       noaction 0
\kp*       noaction *
\kp/       noaction /
\kp-       noaction -
\kp+       noaction +
\kp.       noaction .
\kp,       noaction ,
H          help
h          help
\k1        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

(pssst — those ## lines in the middle there are comment lines, so they don't do anything, they're just notes for you. 💜)

✨ more parts coming bestie, don't go anywhere ✨

👑 PRECEDENCE 👑

okay so bestie, listen: if you set a command in your lesskey file, it wins. lesskey commands take precedence over the default commands, every single time. no arguments. periodt.

But what if you want a default key GONE? Two ways, and they are not the same vibe:

Drop it in the input file with the action invalid and it's disabled.
Or define it to do literally nothing with the action noaction.

The difference: noaction is similar to invalid, but less gives you an error beep for an invalid command, and 🦗 nothing at all for a noaction command. Silent. Iconic.

And if you want to nuke ALL the default commands at once? Add this control line to the input file:

#stop

That makes all default commands get ignored. This #stop line should be the last line in that section of the file, mkay? Order matters, she's picky.

⚠️ #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. like, genuine, unhinged, "why can't I leave" frustration. don't do that to yourself. 😭

✨ 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
\t           forw-complete
\17          back-complete
\ekt         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
\e\kL        word-left
\ew          word-right
\e\kr        word-right
\e\kR        word-right
\ei          insert
\ki          insert
\ex          delete
\kx          delete
\eX          word-delete
\ekx         word-delete
\kX          word-delete
\e\b         word-backspace
\kB          word-backspace
\e0          home
\kh          home
\e$          end
\ke          end
\ek          up
\ku          up
\ej          down
\kd          down
^G           abort
\kp1         end
\kp2         down
\kp4         left
\kp6         right
\kp7         home
\kp8         up
\kp0         noaction 0
\kp*         noaction *
\kp/         noaction /
\kp-         noaction -
\kp+         noaction +
\kp.         noaction .
\kp,         noaction ,
\e[M         mouse
\e[<         mouse6

like… look at her. a whole keymap. we love a complete reference. 🧚

🦋 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. And if a variable is specified in the system environment and also in a lesskey file, the value in the lesskey file takes precedence. 💅 the lesskey file is the main character here.

💜 the `+=` situation

If the variable name is followed by += rather than =, the string is appended to the variable's existing value. But heads up, this currently works only if any += lines immediately follow the same variable's original definition (with an = line), without any intervening definitions of other variables. 😤

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 whitespace is desired, it should be appended to the end of the preceding line. (It can't be added to the beginning of the += string because space after the equals sign is ignored, as noted above.)

🌈 variable expansion & replacement

In the string after the = sign, a substring of the form ${NAME} is replaced with the value of the environment variable NAME. Where does that value come from? Any of these, fr fr:

the system environment
an earlier lesskey file
an earlier definition in the current lesskey file

Simple text replacements can be performed by using the syntax ${NAME/STRING/REPL}. This replaces all instances of STRING in the named environment variable with the text REPL. STRING is matched using a simple text comparison — no metacharacters are supported, bestie, sorry. 🙈

An instance of a slash or a right curly bracket in STRING or REPL must be escaped by preceding it with two backslashes. If REPL is an empty string, all instances of STRING are removed. A slash immediately before the right curly bracket may be omitted. And multiple replacements? Yes queen — use the syntax ${NAME/STRING1/REPL1/STRING2/REPL2} and so on. 🌟

🎀 CONDITIONAL CONFIGURATION 🎀

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 less matches the operator. This can be helpful if a lesskey file is used by different versions of less. ✨ very "one config, many machines" of her.

For example, suppose that a new command named sideways-search is added in less version 777. Then the following line would assign the command to the Q key, but only in versions of less which 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 less before version 594. In those older versions, all #version lines are ignored. so if you're on ancient less, these lines are just decorative. sorry bestie.

🌸 EXAMPLE 🌸

The following input file sets the -i and -S options when less 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

👀 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 \340 in a lesskey file. noted, memorized, screenshotted. 📸

⭐ COPYRIGHT ⭐

less is part of the GNU project and is free software. You can redistribute it and/or modify it under the terms of either:

the GNU General Public License as published by the Free Software Foundation; or
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 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. 🫶

🫶 AUTHOR 🫶

Mark Nudelman

Report bugs at https://github.com/gwsw/less/issues.

okay that's the whole page bestie, we ate and left no crumbs. 🍓 this was lesskey(5) from less 710, dated 08 Sep 2026 — go forth and remap ur keys, u icon, u legend. 💖✨🎀

📦 where this page comes from

fedora 43: less 710-1.fc43 · (GPL-3.0-only OR BSD-2-Clause) AND GPL-2.0-or-later
fedora 44: less 710-1.fc44 · (GPL-3.0-only OR BSD-2-Clause) AND GPL-2.0-or-later
nixpkgs unstable: less 710
💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on 2026-11-03: a language model's rewrite of the original, under its terms

LESSKEY(5)

💖 LESSKEY(5) 💖

✨ NAME ✨

🌸 DESCRIPTION 🌸

👑 COMMAND SECTION 👑

💫 The "extra" string (this is the good part) 💫

🦋 EXAMPLE 🦋

👑 PRECEDENCE 👑

✨ LINE EDITING SECTION ✨

🌸 EXAMPLE 🌸

🦋 LESS ENVIRONMENT VARIABLES 🦋

💜 the += situation

🌈 variable expansion & replacement

🎀 CONDITIONAL CONFIGURATION 🎀

🌸 EXAMPLE 🌸

👀 SEE ALSO 👀

💀 WARNINGS 💀

⭐ COPYRIGHT ⭐

🫶 AUTHOR 🫶

💜 the `+=` situation