The input file 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 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 which must be preceded by backslash include caret, space, tab and the backslash itself. Blank lines and lines which start with a pound sign (#) are ignored.
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 -V flag causes lesskey to print its version number and immediately exit. Other flags and arguments are ignored.
\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 z forw-window w back-window F forw-forever 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 \u undo-hilite 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 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
#stop
This will cause all default commands to be ignored. The #stop line should be the last line in that section of the file. (Another section, introduced by #line-edit, may follow the #stop line.)
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-edit
Following this line is a list of keys and actions, one per line as in the example below.
#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