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 458 and 466
16 * Don't overwrite history file; just append to it.
18 * New command ESC-G goes to end of currently buffered data in a pipe.
20 * In more-compatible mode, make the -p option apply to every file opened,
21 not just the first one.
23 * In more-compatible mode, change the -e option to work like -E, not -EF.
25 * Treat multiple CRs before LF are like one CR (all the CRs are hidden).
27 * Ignore -u/-U setting while viewing help file, so that
28 underline and bold chars are displayed correctly.
30 * Improve detection of "binary" files in UTF-8 mode.
32 * Fix bug with ++ commands.
34 * Fix bugs and improve performance in ampersand filtering.
36 * Automate construction of Unicode tables from Unicode database.
38 ======================================================================
40 Major changes between "less" versions 451 and 458
42 * Allow backslash escaping of metacharacters in LESS environment variable
43 after the --use-backslash option.
45 * Don't quit if syntax errors are found in command line options.
47 * Increase sizes of some internal buffers.
49 * Fix configure bug with --with-regex=none.
51 * Fix crash with "stty rows 0".
53 * Fix Win32 attribute display bug.
55 * Fix display bug when using up/down arrow on the command line.
57 ======================================================================
59 Major changes between "less" versions 444 and 451
61 * Add ESC-F command to keep reading data until a pattern is found.
63 * Use exit code of LESSOPEN script if LESSOPEN starts with "||".
65 * When up/down arrow is used on the command line immediately after
66 typing text, the next command starting with that text is found.
68 * Add support for GNU regex.
70 * Add configure option --with-regex=none and fix compile errors
71 when compiling with no regex library.
73 * Fix bugs handling SGR sequences in Win32.
75 * Fix possible crashes caused by malformed LESSOPEN or
78 * Fix bug highlighting text which is discontiguous in the file
79 due to backspace processing.
81 * Fix bug in displaying status column when scrolling backwards
82 with -J and -S in effect.
84 ======================================================================
86 Major changes between "less" versions 443 and 444
88 * Fix bug in unget handling that can cause strange effects on the
91 * Remove vestiges of obsolete -l option that can cause a crash.
93 ======================================================================
95 Major changes between "less" versions 436 and 443
97 * Change search behavior such that when a search is given an explicit
98 pattern, the entire displayed screen is included in the search and
99 not just the portion after the target line.
101 * Add -A option to change search behavior to the old way: only
102 the portion of the screen after the target line is searched.
104 * Add %F formatting to prompt strings, replaced by the last component
107 * Control-G while editing a command exits the command.
109 * Less now exits with status 2 if control-C is pressed and -K is in effect.
111 * Fix "ungetc overflow" when passing long commands via the -p option.
113 * Fix bug in using line filtering via the & command
114 in combination with -i and -I.
116 * Fix bug in handling negative arguments to the -j option.
118 * Fix bug in handling %t in prompt strings.
120 * Improve handling of long option names.
122 * Improve percentage calculation for very large files.
124 ======================================================================
126 Major changes between "less" versions 429 and 436
128 * Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
130 * Allow a fraction as the argument to the -# (--shift) option.
132 * Fix highlight bug when underlined/overstruck text matches at end of line.
134 * Fix non-regex searches with ctrl-R.
136 ======================================================================
138 Major changes between "less" versions 424 and 429
140 * LESSOPEN pipe will now be used on standard input, if the LESSOPEN
141 environment variable begins with "|-".
143 * The -D option with one number now means use the normal background color.
145 * Don't change permissions on history file if it is not a regular file.
147 * Fix non-ANSI-compliant code that caused problems with some compilers.
149 * Fix binary file detection in UTF-8 mode.
151 * Fix display problems with long lines on "ignaw" terminals.
153 * Fix problem interrupting the line number calculation for initial prompt.
155 * Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
157 * Fix highlight bug when searching for underlined/overstruck text.
159 ======================================================================
161 Major changes between "less" versions 418 and 424
163 * New "&" command allows filtering of lines based on a pattern.
165 * Status column now displays a search match, even if the matched
166 string is scrolled off screen because -S is in effect.
168 * Improve behavior of -F option.
170 * Allow CSI character (0x9B) to work in UTF-8 mode.
172 * Output carriage return at startup in case terminal doesn't default
175 * Fix bug in '' (quote, quote) command after G command.
177 ======================================================================
179 Major changes between "less" versions 416 and 418
181 * Color escape sequences are now supported in WIN32 build.
183 * Makefile now uses EXEEXT feature of autoconf.
185 * Fix search bug when using -R and text contains ANSI color escape sequences.
187 * Fix crash when using -r with UTF-8 text containing 0x9B bytes.
189 * Fix display bug when using ' command to move less than one page forward.
191 * Update GPL to version 3.
193 ======================================================================
195 Major changes between "less" versions 409 and 416
197 * New --follow-name option makes F command follow the name of a file
198 rather than the file descriptor if an open file is renamed.
200 * Make searching with -i/-I work correctly with non-ASCII text.
204 ======================================================================
206 Major changes between "less" versions 406 and 409
208 * Support CSI escape sequences, like SGR escape sequences.
210 * Fix bug which caused screen to fail to repaint when window is resized.
212 * Fix bug in using -i and -I flags with non-ASCII text.
214 * Fix configure bug on systems which don't support langinfo.h.
216 * Fix crash when searching text containing certain invalid UTF-8 sequences.
218 ======================================================================
220 Major changes between "less" versions 394 and 406
222 * Allow decimal point in number for % (percent) command.
224 * Allow decimal point in number for -j option (fraction of screen height).
226 * Make n command fetch previous pattern from history file on first search.
228 * Don't rewrite history file if it has not changed.
230 * Don't move to bottom of screen on first page.
232 * Don't output extraneous newlines, so copy & pasting lines from the
235 * The -c option has been made identical with the -C option.
237 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
238 that no history file should be used.
240 * Search can now find text which follows a null byte, if the PCRE
241 library is used, or if no-regex searching (ctrl-R) is used.
243 * Better compatibility with POSIX more specification.
245 * Make -f work for directories.
247 * Make "t" cmd traverse tags in the correct order.
249 * Allow a few binary characters in the input file before warning
250 that the file is binary.
252 * Don't warn that file is binary if it merely contains ANSI color sequences
255 * Update Unicode character tables.
257 * Support DESTDIR in Makefile.
259 * Fix bug when filename contains certain shell metacharacters such as "$".
261 * Fix bug when resizing the window while waiting for input from a pipe.
263 * Fix configure bugs.
265 ======================================================================
267 Major changes between "less" versions 382 and 394
269 * Add history file to save search and shell command history between
272 * Improve behavior of history list for search and shell commands.
274 * Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
276 * Improve handling of UTF-8 files and commands, including better
277 line wrapping and handling double-width chars.
279 * Added LESSUTFBINFMT environment variable to control display of
280 non-printable characters in a UTF-8 file.
282 * Add --with-secure option to configure, to make it easier to
283 build a secure version of less.
285 * Show search matches in the status column even if search highlights
286 are disabled via the -G option or the ESC-u command.
288 * Improve performance when the file contains very long lines.
290 * Add "windows" charset.
292 * Add man page for lessecho.
294 * Add support for erase2 character, treated same as erase.
296 * Use ASCII lowercase/uppercase logic when operating on the command line.
298 * Update makefile for Borland C++ 5.5.1.
300 * Fix bug in calculating number of pages for %D prompt.
302 * Fix bug in handling tag file error.
304 * Fix obscure bug if input file is deleted while viewing help.
306 * Fix bug handling filenames which include square brackets.
308 * Fix possible buffer overflow in "global" tag search.
310 * Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
312 * Fix buffer overflow in reverse search.
314 ======================================================================
316 Major changes between "less" versions 381 and 382
318 * Removed some old copyrighted code.
319 This probably breaks OS/9 support.
321 ======================================================================
323 Major changes between "less" versions 378 and 381
325 * New -L option to disable LESSOPEN processing.
327 * Further support for large (64 bit) file addressing.
328 Large file support is now set up by the configure script.
331 Replace configure.in, acconfig.h, defines.h.top with configure.ac.
333 * Overstriking underscore with underscore is now bold or underlined
334 depending on context.
336 * Use only 7 spaces for line numbers in -N mode, if possible.
338 * Fix some bugs in handling overstriking in UTF-8 files.
340 * Fix some nroff issues in the man page.
342 ======================================================================
344 Major changes between "less" versions 376 and 378
347 Default buffer space is now 64K as documented.
348 Search highlighting works properly when used with -R.
349 Windows version works properly when input file contains carriage returns.
350 Clean up some compiler warnings.
352 ======================================================================
354 Major changes between "less" versions 358 and 376
356 * -x option can now specify multiple variable-width tab stops.
358 * -X option no longer disables keypad initialization.
359 New option --no-keypad disables keypad initialization.
361 * New commands t and T step through multiple tag matches.
362 Added support for "global(1)" tags
363 (see http://www.gnu.org/software/global/global.html).
365 * New prompt style set by option -Pw defines the message printed
366 while waiting for data in the F command.
368 * System-wide lesskey file now defaults to sysless in etc directory
369 instead of .sysless in bin directory.
370 Use "configure --sysconfdir=..." to change it.
371 (For backwards compatibility, .sysless in bin is still recognized.)
373 * Pressing RightArrow or LeftArrow while entering a number now shifts
374 the display N columns rather than editing the number itself.
376 * Status column (enabled with -J) now shows search results.
378 * Windows version sets window title.
380 * Default LESSCHARSET for MS-DOS versions is now "dos".
382 * Searching works better with ANSI (SGR) escape sequences.
383 ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
385 * Improved performance in reading very large pipes.
387 * Eliminated some dependencies on file offets being 32 bits.
389 * Fixed problems when viewing files with very long lines.
391 * Fixed overstriking in UTF-8 mode, and overstriking tabs.
393 * Improved horizontal shifting of text using -R option with ANSI color.
395 * Improved handling of filenames containing shell metacharacters.
397 * Some fixes for EBCDIC systems.
399 * Some fixes for OS/2 systems.
401 ======================================================================
403 Major changes between "less" versions 354 and 358
405 * Add -J (--status-column) option to display a status column.
407 * Add -# (--shift) option to set default horizontal shift distance.
408 Default horizontal shift distance is now one-half screen width.
410 * Horizontal shifting does not shift line numbers if -N is in effect.
412 * Horizontal shifting acts as though -S were set, to avoid confusion.
414 ======================================================================
417 Major changes between "less" versions 352 and 354
419 * Allow space after numeric-valued command line options.
421 * Fix problem with configuring terminal libraries on some systems.
423 * Add support for PCRE regular expression library.
425 * Add --with-regex option to configure to allow manually selecting
426 a regular expression library.
428 * Fix bug compiling with SECURE = 1.
430 ======================================================================
433 Major changes between "less" versions 346 and 352
435 * Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
437 * Add --with-editor option to configure script.
439 * The -M prompt and = message now show the top and bottom line number.
441 * Fix bug in running the editor on a file whose name contains quotes, etc.
443 * Fix bug in horizontal scrolling of long lines.
445 * Fix bug in doing :d on a file which contains marks.
447 * Fix bug causing cleared lines to sometimes be filled with standout,
448 bold, underline, etc. on certain terminals.
450 * Fixes for MS-DOS (DJGPP) version.
452 ======================================================================
455 Major changes between "less" versions 340 and 346
457 * The UTF-8 character set is now supported.
459 * The default character set is now latin1 rather than ascii.
461 * New option -R (--RAW-CONTROL-CHARS) is like -r but handles
462 long (wrapped) lines correctly, as long as the input contains only
463 normal text and ANSI color escape sequences.
465 * New option -F (--quit-if-one-screen) quits if the text fits on
468 * The -w option now highlights the target line of a g or p command.
470 * A system-wide lesskey file is supported (LESSKEY_SYSTEM).
472 * New escape for prompt strings: %c is replaced by column number.
474 * New escape for prompt strings: %P is replaced by percentage into
475 file, based on line number rather than byte offset.
477 * HOME and END keys now jump to beginning of file or end of file.
479 ======================================================================
482 Major changes between "less" versions 337 and 340
484 * Command line options for less may now be given in either the old
485 single-letter form, or a new long name form (--option-name).
486 See the less man page or "less --help" for the list of long option names.
488 * Command line options for lesskey may now be given in a new long name
489 form. See the lesskey man page for the list of long option names.
491 * New command -- toggles an option using the long option name.
493 * New command __ queries an option using the long option name.
495 * The old -- command is renamed as -!.
497 * If a ^P is entered between the dash and the option letter of the -
498 command, the message describing the new setting is suppressed.
500 * Lesskey files may now contain \k escape sequences to represent the
501 "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
503 * New command :d removes the current file from the list of files.
505 * New option -~ (like -w before version 335)
506 suppresses tildes after end-of-file.
508 * Less is now released under the GNU General Public License.
510 ======================================================================
513 Major changes between "less" versions 335 and 337
515 * Fixed bugs in "make install".
517 ======================================================================
520 Major changes between "less" versions 332 and 335
522 * The old -w flag (suppress tildes after end-of-file) has been removed.
524 * New -w flag highlights the first new line after a forward-screen.
526 * New -W flag highlights the first new line after any forward movement.
528 * Window resize works even if LINES and/or COLUMNS environment
529 variables are incorrect.
531 * New percent escapes for prompt strings:
532 %d is replaced by the page number, and
533 %D is replaced by the number of pages in the file.
535 * Added charsets "iso8859" and "ebcdic".
537 * In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
539 * Fixed some bugs causing incorrect display on DOS/Windows.
541 ======================================================================
544 Major changes between "less" versions 330 and 332
546 * Filenames from the command line are entered into the command history,
547 so UPARROW/DOWNARROW can be used to retrieve them from the :e command.
549 * Now works correctly on Windows when using a scrolling terminal
550 window (buffer larger than display window).
552 * On Windows, now restores the console screen on exit.
553 Use -X to get the old behavior.
555 * Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
557 * Fixed bug on Windows when piping output of an interactive program.
559 * Fixed bug in tags file processing when tags file has DOS-style
560 line terminators (CR/LF).
562 * Fixed compilation problem on OS/2.
564 ======================================================================
567 Major changes between "less" versions 321 and 330
569 * Now supports filenames containing spaces (in double quotes).
570 New option -" can be used to change the quoting characters.
572 * In filename completion, a slash is appended to a directory name.
573 If the environment variable LESSSEPARATOR is set, the value of
574 that variable, rather than a slash, is appended.
576 * LeftArrow and RightArrow are same as ESC-[ and ESC-].
578 * Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
580 * A "quit" command defined in a lesskey file may now have an "extra"
581 string, which is used to return an exit code from less when it quits.
583 * New environment variables LESSMETACHARS and LESSMETAESCAPE provide
584 more control over how less interfaces to the shell.
586 * Ported to Microsoft Visual C compiler for Windows.
588 * Ported to DJGPP compiler for MS-DOS.
592 ======================================================================
595 Major changes between "less" versions 291 and 321
597 * Command line at bottom of screen now scrolls, so it can be longer
598 than the screen width.
600 * New commands ESC-] and ESC-[ scroll the display horizontally.
602 * New command ESC-SPACE scrolls forward a full screen, even if it
605 * Alternate modifiers for search commands: ^N is same as !,
606 ^F is same as @, and ^E is same as *.
608 * New modifier for search commands: ^K means highlight the matches
609 currently on-screen, but don't move to the first match.
611 * New modifier for search commands: ^R means don't use regular
612 expressions in the search.
614 * Environment variable LESSKEY gives name of default lesskey file.
616 * Environment variable LESSSECURE will force less to run in
619 * Command line argument "--" signals that the rest of the arguments
620 are files (not option flags).
622 * Help file (less.hlp) is no longer installed. Help text is now
623 embedded in the less executable itself.
625 * Added -Ph to change the prompt for the help text.
626 Added -Ps to change the default short prompt (same as plain -P).
628 * Ported to the Borland C compiler for MS-DOS.
630 * Ported to Windows 95 & Windows NT.
634 * Ported to GNU Hurd.
636 ======================================================================
639 Major changes between "less" versions 290 and 291
641 * Less environment variables can be specified in lesskey files.
643 * Fixed MS-DOS build.
645 ======================================================================
648 Major changes between "less" versions 278 and 290
650 * Accepts GNU-style options "--help" and "--version".
652 * OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
656 ======================================================================
659 Major changes between "less" versions 252 and 278
661 * A LESSOPEN preprocessor may now pipe the converted file data to less,
662 rather than writing it to a temporary file.
664 * Search pattern highlighting has been fixed. It now highlights
665 reliably, even if a string is split across two screen lines,
668 * The -F flag (which suppress search highlighting) has been changed
669 to -G. A new flag, -g, changes search highlighting to highlight
670 only the string found by the last search command, instead of all
671 strings which match the last search command.
673 * New flag -I acts like -i, but ignores case even if the search
674 pattern contains uppercase letters.
676 * Less now checks for the environment variable VISUAL before EDITOR.
680 ======================================================================
683 Major changes between "less" versions 237 and 252
685 * Changes in line-editing keys:
686 The literal key is now ^V or ^A rather than \ (backslash).
687 Filename completion commands (TAB and ^L) are disabled
688 when typing a search pattern.
690 * Line-editing command keys can be redefined using lesskey.
692 * Lesskey with no input file defaults to $HOME/.lesskey
693 rather than standard input.
695 * New option -V displays version number of less.
697 * New option -V displays version number of lesskey.
699 * Help file less.hlp is now installed by default in /usr/local/share
700 rather than /usr/local/lib.
703 ======================================================================
706 Major changes between "less" versions 170 and 237
708 * By popular demand, text which matches the current search pattern
709 is highlighted. New -F flag disables this feature.
711 * Henry Spencer's regexp.c is now included, for systems which do not
712 have a regular expression library.
713 regexp.c is Copyright (c) 1986 by University of Toronto.
715 * New line-editing keys, including command history (arrow keys) and
716 filename completion (TAB).
718 * Input preprocessor allows modification of input files (e.g. uncompress)
719 via LESSOPEN/LESSCLOSE environment variables.
721 * New -X flag disables sending termcap "ti" and "te" (initialize and
722 deinitialize) strings to the terminal.
724 * Changing -i from within less now correctly affects a subsequent
727 * Searching for underlined or overstruck text now works when the -u
728 flag is in effect, rather than the -i flag.
730 * Use setlocale (LANG and LC_CTYPE environment variables) to determine
731 the character set if LESSCHARSET/LESSCHARDEF are not set.
733 * The default format for displaying binary characters is now standout
734 (reverse video) rather than blinking. This can still be changed by
735 setting the LESSBINFMT environment variable.
737 * Use autoconf installation technology.
741 ********************************
742 Things that may surprise you
743 ********************************
745 * When you enter text at the bottom of the screen (search string,
746 filename, etc.), some keys act different than previously.
747 Specifically, \ (backslash), ESC, TAB, BACKTAB, and control-L
748 now have line editing functions.
750 * Some previous unofficial versions of less were able to display
751 compressed files. The new LESSOPEN/LESSCLOSE feature now provides
752 this functionality in a different way.
754 * Some previous unofficial versions of less provided a -Z flag to
755 set the number of lines of text to retain between full screen scrolls.
756 The -z-n flag (that is, -z with a negative number) provides this
760 ======================================================================
763 Major changes between "less" versions 123 and 170
765 * New option -j allows target lines to be positioned anywhere on screen.
767 * New option -S truncates displayed line at the screen width,
768 rather than wrapping onto the next line.
770 * New option -y limits amount of forward scroll.
772 * New option -T specifies a "tags" file.
774 * Non-printable, non-control characters are displayed in octal.
775 Such characters, as well as control characters, are displayed
778 * New command -+ sets an option to its default.
779 * New command -- sets an option to the opposite of its default.
781 * Lesskey file may have a string appended to a key's action,
782 which acts as though typed in after the command.
784 * New commands ESC-^F and ESC-^B match arbitrary types of brackets.
786 * New command F monitors a growing file (like "tail -f").
788 * New command | pipes a section of the input file into a shell command.
790 * New command :x directly jumps to a file in the command line list.
792 * Search commands have been enhanced and reorganized:
793 n Repeat search, same direction.
794 N Repeat search, opposite direction.
795 ESC-/ Search forward thru file boundaries
796 ESC-? Search backward thru file boundaries
797 ESC-n Repeat search thru file boundaries, same direction.
798 ESC-N Repeat search thru file boundaries, opposite direction.
799 Special character * causes search to search thru file boundaries.
800 Special character @ causes search to begin at start/end of file list.
802 * Examining a new file adds it to the command line list.
803 A list of files, or an expression which matches more than one file,
804 may be examined; all of them are added to the command line list.
806 * Environment variables LESSCHARSET and LESSCHARDEF can define
807 a non-ASCII character set.
809 * Partial support for MSDOS, including options -R for repainting screen
810 on quit, -v/-V to select video mode, and -W to change window size.
813 ======================================================================
816 Major changes between "less" versions 97 and 123
818 * New option (-N) causes line numbers to be displayed in the
819 text of the file (like vi "set nu").
821 * New option (-?) prints help message immediately.
823 * New option (-r) displays "raw" control characters, without
824 mapping them to ^X notation.
826 * New option (-f) forces less to open non-regular files
829 * New option (-k) can be used to specify lesskey files by name.
831 * New option (-y) can be used to set a forward scroll limit
832 (like -h sets a backward scroll limit).
834 * File marks (set by the m command) are now preserved when a new
835 file is edited. The ' command can thus be used to switch files.
837 * New command ESC-/ searches all files (on the command line)
840 * New command ESC-n repeats previous search, spanning files.
842 * The N command has been changed to repeat the previous search
843 in the reverse direction. The old N command is still available
846 * New command ESC-N repeats previous search in the reverse
847 direction and spanning files.
849 * 8 bit characters are now supported. A new option (-g) can be
850 used to strip off the eighth bit (the previous behavior).
852 * Options which take a following string (like -t) may now
853 optionally have a space between the option letter and the string.
855 * Six new commands { } ( ) [ and ] can be used to match
856 brackets of specific types, similar to vi % command.
858 * New commands z and w move forward/backward one window and
859 simultaneously set the window size.
861 * Prompt string expansion now has %L for line number of the last
862 line in the file, and %E for the name of the editor.
863 Also, % escapes which refer to a line (b=bottom, t=top, etc.)
864 can use j for the jump target line.
866 * New environment variable LESSEDIT can be used to tailor the
867 command string passed to the editor by the v command.
869 * Examining a file which was previously examined will return
870 to the same position in the file.
872 * A "%" is expanded to the current filename and a "#" to the
873 previous filename, in both shell commands and the E command.
874 (Previously % worked only in shell commands and # worked
875 only in the E command.)
877 * New command ":ta" is equivalent to "-t".
879 * New command "s" is equivalent to "-l".
881 * The - command may be followed by "+X" to revert to the default
882 for option X, or "-X" to get the opposite of the default.
884 * Lesskey files may now include characters after the action as
885 extra input to be parsed after the action; for example:
886 "toggle-option X" to toggle a specific option X.