# lesskey

## NAME



           lesskey - customize key bindings for less
    


## SYNOPSIS (deprecated)



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


## SCOPE



           This document describes the format of the **lesskey** source file,
           which is used by **less** version 582 and later.  In previous versions
           of **less** , a separate program called **lesskey** was used to compile the
           **lesskey** source file into a format understood by **less**.  This
           compilation step is no longer required and the **lesskey** program is
           therefore deprecated, although the file format remains supported
           by **less** itself.
    


## DESCRIPTION



           A **lesskey** file specifies a set of key bindings and environment
           variables to be used by subsequent invocations of **less**.
    


## FILE FORMAT



           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
                  Customizes command key bindings.
    
           #line-edit
                  Customizes line-editing key bindings.
    
           #env   Defines environment variables.
    
           Blank lines are ignored.  Any text that follows an unescaped hash
           mark (#) in a line is ignored, except as noted below.
    


## 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_ <whitespace> [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 lists in the
           EXAMPLE sections 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   (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
                character is to be taken literally.  Characters which must be
                preceded by backslash include caret, space, tab, hash mark
                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, the ASCII value of the 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**.  Documentation on each command can be found in the
           **less** 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
                \ej        forw-newline
                \ek        back-newline
                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
                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
                \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
                ^O^N       osc8-forw-search
                ^On        osc8-forw-search
                ^O^P       osc8-back-search
                ^Op        osc8-back-search
                ^O^O       osc8-open
                &          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
                \e[M       mouse
                \e[<       mouse6
                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
                \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
                \e[M         mouse
                \e[<         mouse6
    


## 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.
    
           If the variable name is followed by += rather than =, the string
           is appended 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 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 cannot be added to
           the beginning of the += string because space after the equals sign
           is ignored, as noted above.)
    
           In the string after the = sign, a substring of the form ${NAME} is
           replaced with the value of the environment variable "NAME".  The
           value of the variable may come from either the system environment,
           an earlier lesskey file, or 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.  An instance of slash or 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.  Multiple replacements may be performed by using
           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**(or **lesskey**) matches the
           operator.  This can be helpful if a lesskey file is used by
           different versions of **less**.
    
           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** and **lesskey** before
           version 594.  In those older versions, all #version lines are
           ignored.
    


## 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
    


## 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.
    


* * *