4 ======================================================================
6 For the latest news about less, see the "less" Web page:
7 http://www.greenwoodsoftware.com/less
8 You can also download the latest version of less from there.
10 To report bugs, suggestions or comments, send email to bug-less@gnu.org
12 ======================================================================
14 Major changes between "less" versions 481 and 487
16 * New commands ESC-{ and ESC-} to shift to start/end of displayed lines.
18 * Make search highlights work correctly when changing caselessness with -i.
20 * New option -Da in Windows version to enable SGR mode.
22 * Fix "nothing to search" error when top or bottom line on screen is empty.
24 * Fix bug when terminal has no "cm" termcap entry.
26 * Fix incorrect display when entering double-width chars in search string.
28 * Fix bug in Unicode handling that missed some double width characters.
30 * Update Unicode database to 9.0.0.
32 ======================================================================
34 Major changes between "less" versions 458 and 481
36 * Don't overwrite history file; just append to it.
38 * New command ESC-G goes to end of currently buffered data in a pipe.
40 * Disable history feature when compiled with LESSHISTFILE set to "-".
42 * In more-compatible mode, make the -p option apply to every file opened,
43 not just the first one.
45 * In more-compatible mode, change the -e option to work like -E, not -EF.
47 * Treat multiple CRs before LF are like one CR (all the CRs are hidden).
49 * Allow "extra" string in lesskey file to append to a multi-char command
50 (like a search pattern), without executing the command.
52 * Ignore -u/-U setting while viewing help file, so that
53 underline and bold chars are displayed correctly.
55 * Improve detection of "binary" files in UTF-8 mode.
57 * Fix bug with ++ commands.
59 * Fix bug where prompt was sometimes not displayed with +G.
61 * Fix possible memory corruption
63 * Fix bugs and improve performance in ampersand filtering.
65 * Automate construction of Unicode tables from Unicode database.
67 * Allow %% escape sequence in LESSOPEN variable.
69 ======================================================================
71 Major changes between "less" versions 451 and 458
73 * Allow backslash escaping of metacharacters in LESS environment variable
74 after the --use-backslash option.
76 * Don't quit if syntax errors are found in command line options.
78 * Increase sizes of some internal buffers.
80 * Fix configure bug with --with-regex=none.
82 * Fix crash with "stty rows 0".
84 * Fix Win32 attribute display bug.
86 * Fix display bug when using up/down arrow on the command line.
88 ======================================================================
90 Major changes between "less" versions 444 and 451
92 * Add ESC-F command to keep reading data until a pattern is found.
94 * Use exit code of LESSOPEN script if LESSOPEN starts with "||".
96 * When up/down arrow is used on the command line immediately after
97 typing text, the next command starting with that text is found.
99 * Add support for GNU regex.
101 * Add configure option --with-regex=none and fix compile errors
102 when compiling with no regex library.
104 * Fix bugs handling SGR sequences in Win32.
106 * Fix possible crashes caused by malformed LESSOPEN or
109 * Fix bug highlighting text which is discontiguous in the file
110 due to backspace processing.
112 * Fix bug in displaying status column when scrolling backwards
113 with -J and -S in effect.
115 ======================================================================
117 Major changes between "less" versions 443 and 444
119 * Fix bug in unget handling that can cause strange effects on the
122 * Remove vestiges of obsolete -l option that can cause a crash.
124 ======================================================================
126 Major changes between "less" versions 436 and 443
128 * Change search behavior such that when a search is given an explicit
129 pattern, the entire displayed screen is included in the search and
130 not just the portion after the target line.
132 * Add -A option to change search behavior to the old way: only
133 the portion of the screen after the target line is searched.
135 * Add %F formatting to prompt strings, replaced by the last component
138 * Control-G while editing a command exits the command.
140 * Less now exits with status 2 if control-C is pressed and -K is in effect.
142 * Fix "ungetc overflow" when passing long commands via the -p option.
144 * Fix bug in using line filtering via the & command
145 in combination with -i and -I.
147 * Fix bug in handling negative arguments to the -j option.
149 * Fix bug in handling %t in prompt strings.
151 * Improve handling of long option names.
153 * Improve percentage calculation for very large files.
155 ======================================================================
157 Major changes between "less" versions 429 and 436
159 * Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
161 * Allow a fraction as the argument to the -# (--shift) option.
163 * Fix highlight bug when underlined/overstruck text matches at end of line.
165 * Fix non-regex searches with ctrl-R.
167 ======================================================================
169 Major changes between "less" versions 424 and 429
171 * LESSOPEN pipe will now be used on standard input, if the LESSOPEN
172 environment variable begins with "|-".
174 * The -D option with one number now means use the normal background color.
176 * Don't change permissions on history file if it is not a regular file.
178 * Fix non-ANSI-compliant code that caused problems with some compilers.
180 * Fix binary file detection in UTF-8 mode.
182 * Fix display problems with long lines on "ignaw" terminals.
184 * Fix problem interrupting the line number calculation for initial prompt.
186 * Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
188 * Fix highlight bug when searching for underlined/overstruck text.
190 ======================================================================
192 Major changes between "less" versions 418 and 424
194 * New "&" command allows filtering of lines based on a pattern.
196 * Status column now displays a search match, even if the matched
197 string is scrolled off screen because -S is in effect.
199 * Improve behavior of -F option.
201 * Allow CSI character (0x9B) to work in UTF-8 mode.
203 * Output carriage return at startup in case terminal doesn't default
206 * Fix bug in '' (quote, quote) command after G command.
208 ======================================================================
210 Major changes between "less" versions 416 and 418
212 * Color escape sequences are now supported in WIN32 build.
214 * Makefile now uses EXEEXT feature of autoconf.
216 * Fix search bug when using -R and text contains ANSI color escape sequences.
218 * Fix crash when using -r with UTF-8 text containing 0x9B bytes.
220 * Fix display bug when using ' command to move less than one page forward.
222 * Update GPL to version 3.
224 ======================================================================
226 Major changes between "less" versions 409 and 416
228 * New --follow-name option makes F command follow the name of a file
229 rather than the file descriptor if an open file is renamed.
231 * Make searching with -i/-I work correctly with non-ASCII text.
235 ======================================================================
237 Major changes between "less" versions 406 and 409
239 * Support CSI escape sequences, like SGR escape sequences.
241 * Fix bug which caused screen to fail to repaint when window is resized.
243 * Fix bug in using -i and -I flags with non-ASCII text.
245 * Fix configure bug on systems which don't support langinfo.h.
247 * Fix crash when searching text containing certain invalid UTF-8 sequences.
249 ======================================================================
251 Major changes between "less" versions 394 and 406
253 * Allow decimal point in number for % (percent) command.
255 * Allow decimal point in number for -j option (fraction of screen height).
257 * Make n command fetch previous pattern from history file on first search.
259 * Don't rewrite history file if it has not changed.
261 * Don't move to bottom of screen on first page.
263 * Don't output extraneous newlines, so copy & pasting lines from the
266 * The -c option has been made identical with the -C option.
268 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
269 that no history file should be used.
271 * Search can now find text which follows a null byte, if the PCRE
272 library is used, or if no-regex searching (ctrl-R) is used.
274 * Better compatibility with POSIX more specification.
276 * Make -f work for directories.
278 * Make "t" cmd traverse tags in the correct order.
280 * Allow a few binary characters in the input file before warning
281 that the file is binary.
283 * Don't warn that file is binary if it merely contains ANSI color sequences
286 * Update Unicode character tables.
288 * Support DESTDIR in Makefile.
290 * Fix bug when filename contains certain shell metacharacters such as "$".
292 * Fix bug when resizing the window while waiting for input from a pipe.
294 * Fix configure bugs.
296 ======================================================================
298 Major changes between "less" versions 382 and 394
300 * Add history file to save search and shell command history between
303 * Improve behavior of history list for search and shell commands.
305 * Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
307 * Improve handling of UTF-8 files and commands, including better
308 line wrapping and handling double-width chars.
310 * Added LESSUTFBINFMT environment variable to control display of
311 non-printable characters in a UTF-8 file.
313 * Add --with-secure option to configure, to make it easier to
314 build a secure version of less.
316 * Show search matches in the status column even if search highlights
317 are disabled via the -G option or the ESC-u command.
319 * Improve performance when the file contains very long lines.
321 * Add "windows" charset.
323 * Add man page for lessecho.
325 * Add support for erase2 character, treated same as erase.
327 * Use ASCII lowercase/uppercase logic when operating on the command line.
329 * Update makefile for Borland C++ 5.5.1.
331 * Fix bug in calculating number of pages for %D prompt.
333 * Fix bug in handling tag file error.
335 * Fix obscure bug if input file is deleted while viewing help.
337 * Fix bug handling filenames which include square brackets.
339 * Fix possible buffer overflow in "global" tag search.
341 * Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
343 * Fix buffer overflow in reverse search.
345 ======================================================================
347 Major changes between "less" versions 381 and 382
349 * Removed some old copyrighted code.
350 This probably breaks OS/9 support.
352 ======================================================================
354 Major changes between "less" versions 378 and 381
356 * New -L option to disable LESSOPEN processing.
358 * Further support for large (64 bit) file addressing.
359 Large file support is now set up by the configure script.
362 Replace configure.in, acconfig.h, defines.h.top with configure.ac.
364 * Overstriking underscore with underscore is now bold or underlined
365 depending on context.
367 * Use only 7 spaces for line numbers in -N mode, if possible.
369 * Fix some bugs in handling overstriking in UTF-8 files.
371 * Fix some nroff issues in the man page.
373 ======================================================================
375 Major changes between "less" versions 376 and 378
378 Default buffer space is now 64K as documented.
379 Search highlighting works properly when used with -R.
380 Windows version works properly when input file contains carriage returns.
381 Clean up some compiler warnings.
383 ======================================================================
385 Major changes between "less" versions 358 and 376
387 * -x option can now specify multiple variable-width tab stops.
389 * -X option no longer disables keypad initialization.
390 New option --no-keypad disables keypad initialization.
392 * New commands t and T step through multiple tag matches.
393 Added support for "global(1)" tags
394 (see http://www.gnu.org/software/global/global.html).
396 * New prompt style set by option -Pw defines the message printed
397 while waiting for data in the F command.
399 * System-wide lesskey file now defaults to sysless in etc directory
400 instead of .sysless in bin directory.
401 Use "configure --sysconfdir=..." to change it.
402 (For backwards compatibility, .sysless in bin is still recognized.)
404 * Pressing RightArrow or LeftArrow while entering a number now shifts
405 the display N columns rather than editing the number itself.
407 * Status column (enabled with -J) now shows search results.
409 * Windows version sets window title.
411 * Default LESSCHARSET for MS-DOS versions is now "dos".
413 * Searching works better with ANSI (SGR) escape sequences.
414 ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
416 * Improved performance in reading very large pipes.
418 * Eliminated some dependencies on file offets being 32 bits.
420 * Fixed problems when viewing files with very long lines.
422 * Fixed overstriking in UTF-8 mode, and overstriking tabs.
424 * Improved horizontal shifting of text using -R option with ANSI color.
426 * Improved handling of filenames containing shell metacharacters.
428 * Some fixes for EBCDIC systems.
430 * Some fixes for OS/2 systems.
432 ======================================================================
434 Major changes between "less" versions 354 and 358
436 * Add -J (--status-column) option to display a status column.
438 * Add -# (--shift) option to set default horizontal shift distance.
439 Default horizontal shift distance is now one-half screen width.
441 * Horizontal shifting does not shift line numbers if -N is in effect.
443 * Horizontal shifting acts as though -S were set, to avoid confusion.
445 ======================================================================
448 Major changes between "less" versions 352 and 354
450 * Allow space after numeric-valued command line options.
452 * Fix problem with configuring terminal libraries on some systems.
454 * Add support for PCRE regular expression library.
456 * Add --with-regex option to configure to allow manually selecting
457 a regular expression library.
459 * Fix bug compiling with SECURE = 1.
461 ======================================================================
464 Major changes between "less" versions 346 and 352
466 * Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
468 * Add --with-editor option to configure script.
470 * The -M prompt and = message now show the top and bottom line number.
472 * Fix bug in running the editor on a file whose name contains quotes, etc.
474 * Fix bug in horizontal scrolling of long lines.
476 * Fix bug in doing :d on a file which contains marks.
478 * Fix bug causing cleared lines to sometimes be filled with standout,
479 bold, underline, etc. on certain terminals.
481 * Fixes for MS-DOS (DJGPP) version.
483 ======================================================================
486 Major changes between "less" versions 340 and 346
488 * The UTF-8 character set is now supported.
490 * The default character set is now latin1 rather than ascii.
492 * New option -R (--RAW-CONTROL-CHARS) is like -r but handles
493 long (wrapped) lines correctly, as long as the input contains only
494 normal text and ANSI color escape sequences.
496 * New option -F (--quit-if-one-screen) quits if the text fits on
499 * The -w option now highlights the target line of a g or p command.
501 * A system-wide lesskey file is supported (LESSKEY_SYSTEM).
503 * New escape for prompt strings: %c is replaced by column number.
505 * New escape for prompt strings: %P is replaced by percentage into
506 file, based on line number rather than byte offset.
508 * HOME and END keys now jump to beginning of file or end of file.
510 ======================================================================
513 Major changes between "less" versions 337 and 340
515 * Command line options for less may now be given in either the old
516 single-letter form, or a new long name form (--option-name).
517 See the less man page or "less --help" for the list of long option names.
519 * Command line options for lesskey may now be given in a new long name
520 form. See the lesskey man page for the list of long option names.
522 * New command -- toggles an option using the long option name.
524 * New command __ queries an option using the long option name.
526 * The old -- command is renamed as -!.
528 * If a ^P is entered between the dash and the option letter of the -
529 command, the message describing the new setting is suppressed.
531 * Lesskey files may now contain \k escape sequences to represent the
532 "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
534 * New command :d removes the current file from the list of files.
536 * New option -~ (like -w before version 335)
537 suppresses tildes after end-of-file.
539 * Less is now released under the GNU General Public License.
541 ======================================================================
544 Major changes between "less" versions 335 and 337
546 * Fixed bugs in "make install".
548 ======================================================================
551 Major changes between "less" versions 332 and 335
553 * The old -w flag (suppress tildes after end-of-file) has been removed.
555 * New -w flag highlights the first new line after a forward-screen.
557 * New -W flag highlights the first new line after any forward movement.
559 * Window resize works even if LINES and/or COLUMNS environment
560 variables are incorrect.
562 * New percent escapes for prompt strings:
563 %d is replaced by the page number, and
564 %D is replaced by the number of pages in the file.
566 * Added charsets "iso8859" and "ebcdic".
568 * In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
570 * Fixed some bugs causing incorrect display on DOS/Windows.
572 ======================================================================
575 Major changes between "less" versions 330 and 332
577 * Filenames from the command line are entered into the command history,
578 so UPARROW/DOWNARROW can be used to retrieve them from the :e command.
580 * Now works correctly on Windows when using a scrolling terminal
581 window (buffer larger than display window).
583 * On Windows, now restores the console screen on exit.
584 Use -X to get the old behavior.
586 * Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
588 * Fixed bug on Windows when piping output of an interactive program.
590 * Fixed bug in tags file processing when tags file has DOS-style
591 line terminators (CR/LF).
593 * Fixed compilation problem on OS/2.
595 ======================================================================
598 Major changes between "less" versions 321 and 330
600 * Now supports filenames containing spaces (in double quotes).
601 New option -" can be used to change the quoting characters.
603 * In filename completion, a slash is appended to a directory name.
604 If the environment variable LESSSEPARATOR is set, the value of
605 that variable, rather than a slash, is appended.
607 * LeftArrow and RightArrow are same as ESC-[ and ESC-].
609 * Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
611 * A "quit" command defined in a lesskey file may now have an "extra"
612 string, which is used to return an exit code from less when it quits.
614 * New environment variables LESSMETACHARS and LESSMETAESCAPE provide
615 more control over how less interfaces to the shell.
617 * Ported to Microsoft Visual C compiler for Windows.
619 * Ported to DJGPP compiler for MS-DOS.
623 ======================================================================
626 Major changes between "less" versions 291 and 321
628 * Command line at bottom of screen now scrolls, so it can be longer
629 than the screen width.
631 * New commands ESC-] and ESC-[ scroll the display horizontally.
633 * New command ESC-SPACE scrolls forward a full screen, even if it
636 * Alternate modifiers for search commands: ^N is same as !,
637 ^F is same as @, and ^E is same as *.
639 * New modifier for search commands: ^K means highlight the matches
640 currently on-screen, but don't move to the first match.
642 * New modifier for search commands: ^R means don't use regular
643 expressions in the search.
645 * Environment variable LESSKEY gives name of default lesskey file.
647 * Environment variable LESSSECURE will force less to run in
650 * Command line argument "--" signals that the rest of the arguments
651 are files (not option flags).
653 * Help file (less.hlp) is no longer installed. Help text is now
654 embedded in the less executable itself.
656 * Added -Ph to change the prompt for the help text.
657 Added -Ps to change the default short prompt (same as plain -P).
659 * Ported to the Borland C compiler for MS-DOS.
661 * Ported to Windows 95 & Windows NT.
665 * Ported to GNU Hurd.
667 ======================================================================
670 Major changes between "less" versions 290 and 291
672 * Less environment variables can be specified in lesskey files.
674 * Fixed MS-DOS build.
676 ======================================================================
679 Major changes between "less" versions 278 and 290
681 * Accepts GNU-style options "--help" and "--version".
683 * OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
687 ======================================================================
690 Major changes between "less" versions 252 and 278
692 * A LESSOPEN preprocessor may now pipe the converted file data to less,
693 rather than writing it to a temporary file.
695 * Search pattern highlighting has been fixed. It now highlights
696 reliably, even if a string is split across two screen lines,
699 * The -F flag (which suppress search highlighting) has been changed
700 to -G. A new flag, -g, changes search highlighting to highlight
701 only the string found by the last search command, instead of all
702 strings which match the last search command.
704 * New flag -I acts like -i, but ignores case even if the search
705 pattern contains uppercase letters.
707 * Less now checks for the environment variable VISUAL before EDITOR.
711 ======================================================================
714 Major changes between "less" versions 237 and 252
716 * Changes in line-editing keys:
717 The literal key is now ^V or ^A rather than \ (backslash).
718 Filename completion commands (TAB and ^L) are disabled
719 when typing a search pattern.
721 * Line-editing command keys can be redefined using lesskey.
723 * Lesskey with no input file defaults to $HOME/.lesskey
724 rather than standard input.
726 * New option -V displays version number of less.
728 * New option -V displays version number of lesskey.
730 * Help file less.hlp is now installed by default in /usr/local/share
731 rather than /usr/local/lib.
734 ======================================================================
737 Major changes between "less" versions 170 and 237
739 * By popular demand, text which matches the current search pattern
740 is highlighted. New -F flag disables this feature.
742 * Henry Spencer's regexp.c is now included, for systems which do not
743 have a regular expression library.
744 regexp.c is Copyright (c) 1986 by University of Toronto.
746 * New line-editing keys, including command history (arrow keys) and
747 filename completion (TAB).
749 * Input preprocessor allows modification of input files (e.g. uncompress)
750 via LESSOPEN/LESSCLOSE environment variables.
752 * New -X flag disables sending termcap "ti" and "te" (initialize and
753 deinitialize) strings to the terminal.
755 * Changing -i from within less now correctly affects a subsequent
758 * Searching for underlined or overstruck text now works when the -u
759 flag is in effect, rather than the -i flag.
761 * Use setlocale (LANG and LC_CTYPE environment variables) to determine
762 the character set if LESSCHARSET/LESSCHARDEF are not set.
764 * The default format for displaying binary characters is now standout
765 (reverse video) rather than blinking. This can still be changed by
766 setting the LESSBINFMT environment variable.
768 * Use autoconf installation technology.
772 ********************************
773 Things that may surprise you
774 ********************************
776 * When you enter text at the bottom of the screen (search string,
777 filename, etc.), some keys act different than previously.
778 Specifically, \ (backslash), ESC, TAB, BACKTAB, and control-L
779 now have line editing functions.
781 * Some previous unofficial versions of less were able to display
782 compressed files. The new LESSOPEN/LESSCLOSE feature now provides
783 this functionality in a different way.
785 * Some previous unofficial versions of less provided a -Z flag to
786 set the number of lines of text to retain between full screen scrolls.
787 The -z-n flag (that is, -z with a negative number) provides this
791 ======================================================================
794 Major changes between "less" versions 123 and 170
796 * New option -j allows target lines to be positioned anywhere on screen.
798 * New option -S truncates displayed line at the screen width,
799 rather than wrapping onto the next line.
801 * New option -y limits amount of forward scroll.
803 * New option -T specifies a "tags" file.
805 * Non-printable, non-control characters are displayed in octal.
806 Such characters, as well as control characters, are displayed
809 * New command -+ sets an option to its default.
810 * New command -- sets an option to the opposite of its default.
812 * Lesskey file may have a string appended to a key's action,
813 which acts as though typed in after the command.
815 * New commands ESC-^F and ESC-^B match arbitrary types of brackets.
817 * New command F monitors a growing file (like "tail -f").
819 * New command | pipes a section of the input file into a shell command.
821 * New command :x directly jumps to a file in the command line list.
823 * Search commands have been enhanced and reorganized:
824 n Repeat search, same direction.
825 N Repeat search, opposite direction.
826 ESC-/ Search forward thru file boundaries
827 ESC-? Search backward thru file boundaries
828 ESC-n Repeat search thru file boundaries, same direction.
829 ESC-N Repeat search thru file boundaries, opposite direction.
830 Special character * causes search to search thru file boundaries.
831 Special character @ causes search to begin at start/end of file list.
833 * Examining a new file adds it to the command line list.
834 A list of files, or an expression which matches more than one file,
835 may be examined; all of them are added to the command line list.
837 * Environment variables LESSCHARSET and LESSCHARDEF can define
838 a non-ASCII character set.
840 * Partial support for MSDOS, including options -R for repainting screen
841 on quit, -v/-V to select video mode, and -W to change window size.
844 ======================================================================
847 Major changes between "less" versions 97 and 123
849 * New option (-N) causes line numbers to be displayed in the
850 text of the file (like vi "set nu").
852 * New option (-?) prints help message immediately.
854 * New option (-r) displays "raw" control characters, without
855 mapping them to ^X notation.
857 * New option (-f) forces less to open non-regular files
860 * New option (-k) can be used to specify lesskey files by name.
862 * New option (-y) can be used to set a forward scroll limit
863 (like -h sets a backward scroll limit).
865 * File marks (set by the m command) are now preserved when a new
866 file is edited. The ' command can thus be used to switch files.
868 * New command ESC-/ searches all files (on the command line)
871 * New command ESC-n repeats previous search, spanning files.
873 * The N command has been changed to repeat the previous search
874 in the reverse direction. The old N command is still available
877 * New command ESC-N repeats previous search in the reverse
878 direction and spanning files.
880 * 8 bit characters are now supported. A new option (-g) can be
881 used to strip off the eighth bit (the previous behavior).
883 * Options which take a following string (like -t) may now
884 optionally have a space between the option letter and the string.
886 * Six new commands { } ( ) [ and ] can be used to match
887 brackets of specific types, similar to vi % command.
889 * New commands z and w move forward/backward one window and
890 simultaneously set the window size.
892 * Prompt string expansion now has %L for line number of the last
893 line in the file, and %E for the name of the editor.
894 Also, % escapes which refer to a line (b=bottom, t=top, etc.)
895 can use j for the jump target line.
897 * New environment variable LESSEDIT can be used to tailor the
898 command string passed to the editor by the v command.
900 * Examining a file which was previously examined will return
901 to the same position in the file.
903 * A "%" is expanded to the current filename and a "#" to the
904 previous filename, in both shell commands and the E command.
905 (Previously % worked only in shell commands and # worked
906 only in the E command.)
908 * New command ":ta" is equivalent to "-t".
910 * New command "s" is equivalent to "-l".
912 * The - command may be followed by "+X" to revert to the default
913 for option X, or "-X" to get the opposite of the default.
915 * Lesskey files may now include characters after the action as
916 extra input to be parsed after the action; for example:
917 "toggle-option X" to toggle a specific option X.