lesskey - specify key bindings for less
lesskey [-o output] [input]
lesskey -V
The lesskey(1) utility is used to specify a set of key bindings to be used by less(1). The input file is a text file that describes the key bindings. If the input file is "-", standard input is read. If no input file is specified, a standard file name 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 that is used by less(1). 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 file name 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(1) will overwrite it.
The -V option causes lesskey(1) to print its version number and immediately exit. If -V 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:
Blank lines and lines that start with a pound sign (#) are ignored, except for the special section header lines.
The command section begins with the line
#command
If the command section is the first section in the file, this line
can be omitted. The command section consists of lines of the form:
string <whitespace> action [extra-string] <newline>
White space is any sequence of one or more spaces, tabs, or both. The string is the command key(s) that invokes the action. The string can 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 can appear literally, or be prefixed by a caret (^) to indicate a control key. A backslash (\) followed by one to three octal digits can be used to specify a character by its octal value. A backslash followed by b, e, n, r, or t specifies BACKSPACE, ESCAPE, NEWLINE, RETURN or TAB, respectively. A backslash followed by any other character indicates that character is to be taken literally. Characters that must be preceded by backslash include caret, space, tab and the backslash itself.
An action can be followed by an "extra" string. When such a command is entered while running less,(1), the action is performed, and then the extra string is parsed, just as if it were typed in to less(1). 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(1) quits, the first character of the extra string is used as its exit status.
The following input file describes the set of default command keys used by less:
#command
\r forw-line
\n forw-line
e forw-line
j 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
b back-screen
^B back-screen
\ev back-screen
\e\40 forw-screen-force
z forw-window
w back-window
F forw-forever
\e[ left-scroll
\e] right-scroll
R repaint-flush
r repaint
^R repaint
^L repaint
g goto-line
< goto-line
\e< goto-line
p percent
% percent
{ 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
\eu undo-hilite
m set-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
s toggle-option o
_ display-option
| pipe
v visual
! shell
+ firstcmd
H help
h help
V version
q quit
:q quit
:Q quit
ZZ quit
Commands specified by lesskey(1) take precedence over the default commands. A default command key can be disabled by including it in the input file with the action "invalid". Alternatively, a key can be defined to do nothing by using the action "noaction". The action "noaction" is similar to "invalid", except that less(1) will give an error beep for an "invalid" command, but not for a "noaction" command. In addition, all default commands can 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.
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 provided in the next section.
The following input file describes the set of default line-editing keys used by less:
#line-edit
\t forw-complete
\17 back-complete
\e\t back-complete
\14 expand
^V literal
^A literal
\el right
\eh left
\eb word-left
\ew word-right
\ei insert
\ex delete
\e\b word-backspace
\e0 home
\e$ end
\ek up
\ej down
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(1).
If a variable is specified in both the system environment and 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(1) configuration information stored in one file.
The following input file sets the -i option whenever less(1) is run, and specifies the character set to be "latin1":
#env
LESS = -i
LESSCHARSET = latin1
It is not possible to specify special keys, such as uparrow, in a keyboard-independent manner. The only way to specify such keys is to specify the escape sequence that a particular keyboard sends when such keys are pressed.
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.
Copyright © 1984, 1985, 1989, 1994, 1995 Mark Nudelman
Comments to: markn@fog.net
less(1)