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 444 and 451
16 * Add ESC-F command to keep reading data until a pattern is found.
18 * Use exit code of LESSOPEN script if LESSOPEN starts with "||".
20 * When up/down arrow is used on the command line immediately after
21 typing text, the next command starting with that text is found.
23 * Add support for GNU regex.
25 * Add configure option --with-regex=none and fix compile errors
26 when compiling with no regex library.
28 * Fix bugs handling SGR sequences in Win32.
30 * Fix possible crashes caused by malformed LESSOPEN or
33 * Fix bug highlighting text which is discontiguous in the file
34 due to backspace processing.
36 * Fix bug in displaying status column when scrolling backwards
37 with -J and -S in effect.
39 ======================================================================
41 Major changes between "less" versions 443 and 444
43 * Fix bug in unget handling that can cause strange effects on the
46 * Remove vestiges of obsolete -l option that can cause a crash.
48 ======================================================================
50 Major changes between "less" versions 436 and 443
52 * Change search behavior such that when a search is given an explicit
53 pattern, the entire displayed screen is included in the search and
54 not just the portion after the target line.
56 * Add -A option to change search behavior to the old way: only
57 the portion of the screen after the target line is searched.
59 * Add %F formatting to prompt strings, replaced by the last component
62 * Control-G while editing a command exits the command.
64 * Less now exits with status 2 if control-C is pressed and -K is in effect.
66 * Fix "ungetc overflow" when passing long commands via the -p option.
68 * Fix bug in using line filtering via the & command
69 in combination with -i and -I.
71 * Fix bug in handling negative arguments to the -j option.
73 * Fix bug in handling %t in prompt strings.
75 * Improve handling of long option names.
77 * Improve percentage calculation for very large files.
79 ======================================================================
81 Major changes between "less" versions 429 and 436
83 * Don't pass "-" to non-pipe LESSOPEN unless it starts with "-".
85 * Allow a fraction as the argument to the -# (--shift) option.
87 * Fix highlight bug when underlined/overstruck text matches at end of line.
89 * Fix non-regex searches with ctrl-R.
91 ======================================================================
93 Major changes between "less" versions 424 and 429
95 * LESSOPEN pipe will now be used on standard input, if the LESSOPEN
96 environment variable begins with "|-".
98 * The -D option with one number now means use the normal background color.
100 * Don't change permissions on history file if it is not a regular file.
102 * Fix non-ANSI-compliant code that caused problems with some compilers.
104 * Fix binary file detection in UTF-8 mode.
106 * Fix display problems with long lines on "ignaw" terminals.
108 * Fix problem interrupting the line number calculation for initial prompt.
110 * Fix SGR emulation when dealing with multiple attributes (eg. bold+underline).
112 * Fix highlight bug when searching for underlined/overstruck text.
114 ======================================================================
116 Major changes between "less" versions 418 and 424
118 * New "&" command allows filtering of lines based on a pattern.
120 * Status column now displays a search match, even if the matched
121 string is scrolled off screen because -S is in effect.
123 * Improve behavior of -F option.
125 * Allow CSI character (0x9B) to work in UTF-8 mode.
127 * Output carriage return at startup in case terminal doesn't default
130 * Fix bug in '' (quote, quote) command after G command.
132 ======================================================================
134 Major changes between "less" versions 416 and 418
136 * Color escape sequences are now supported in WIN32 build.
138 * Makefile now uses EXEEXT feature of autoconf.
140 * Fix search bug when using -R and text contains ANSI color escape sequences.
142 * Fix crash when using -r with UTF-8 text containing 0x9B bytes.
144 * Fix display bug when using ' command to move less than one page forward.
146 * Update GPL to version 3.
148 ======================================================================
150 Major changes between "less" versions 409 and 416
152 * New --follow-name option makes F command follow the name of a file
153 rather than the file descriptor if an open file is renamed.
155 * Make searching with -i/-I work correctly with non-ASCII text.
159 ======================================================================
161 Major changes between "less" versions 406 and 409
163 * Support CSI escape sequences, like SGR escape sequences.
165 * Fix bug which caused screen to fail to repaint when window is resized.
167 * Fix bug in using -i and -I flags with non-ASCII text.
169 * Fix configure bug on systems which don't support langinfo.h.
171 * Fix crash when searching text containing certain invalid UTF-8 sequences.
173 ======================================================================
175 Major changes between "less" versions 394 and 406
177 * Allow decimal point in number for % (percent) command.
179 * Allow decimal point in number for -j option (fraction of screen height).
181 * Make n command fetch previous pattern from history file on first search.
183 * Don't rewrite history file if it has not changed.
185 * Don't move to bottom of screen on first page.
187 * Don't output extraneous newlines, so copy & pasting lines from the
190 * The -c option has been made identical with the -C option.
192 * Allow "/dev/null" as synomym for "-" in LESSHISTFILE to indicate
193 that no history file should be used.
195 * Search can now find text which follows a null byte, if the PCRE
196 library is used, or if no-regex searching (ctrl-R) is used.
198 * Better compatibility with POSIX more specification.
200 * Make -f work for directories.
202 * Make "t" cmd traverse tags in the correct order.
204 * Allow a few binary characters in the input file before warning
205 that the file is binary.
207 * Don't warn that file is binary if it merely contains ANSI color sequences
210 * Update Unicode character tables.
212 * Support DESTDIR in Makefile.
214 * Fix bug when filename contains certain shell metacharacters such as "$".
216 * Fix bug when resizing the window while waiting for input from a pipe.
218 * Fix configure bugs.
220 ======================================================================
222 Major changes between "less" versions 382 and 394
224 * Add history file to save search and shell command history between
227 * Improve behavior of history list for search and shell commands.
229 * Add -K (or --quit-on-intr) option to make less exit immediately on ctrl-C.
231 * Improve handling of UTF-8 files and commands, including better
232 line wrapping and handling double-width chars.
234 * Added LESSUTFBINFMT environment variable to control display of
235 non-printable characters in a UTF-8 file.
237 * Add --with-secure option to configure, to make it easier to
238 build a secure version of less.
240 * Show search matches in the status column even if search highlights
241 are disabled via the -G option or the ESC-u command.
243 * Improve performance when the file contains very long lines.
245 * Add "windows" charset.
247 * Add man page for lessecho.
249 * Add support for erase2 character, treated same as erase.
251 * Use ASCII lowercase/uppercase logic when operating on the command line.
253 * Update makefile for Borland C++ 5.5.1.
255 * Fix bug in calculating number of pages for %D prompt.
257 * Fix bug in handling tag file error.
259 * Fix obscure bug if input file is deleted while viewing help.
261 * Fix bug handling filenames which include square brackets.
263 * Fix possible buffer overflow in "global" tag search.
265 * Fix possible buffer overflow in usage of LESSOPEN and LESSCLOSE.
267 * Fix buffer overflow in reverse search.
269 ======================================================================
271 Major changes between "less" versions 381 and 382
273 * Removed some old copyrighted code.
274 This probably breaks OS/9 support.
276 ======================================================================
278 Major changes between "less" versions 378 and 381
280 * New -L option to disable LESSOPEN processing.
282 * Further support for large (64 bit) file addressing.
283 Large file support is now set up by the configure script.
286 Replace configure.in, acconfig.h, defines.h.top with configure.ac.
288 * Overstriking underscore with underscore is now bold or underlined
289 depending on context.
291 * Use only 7 spaces for line numbers in -N mode, if possible.
293 * Fix some bugs in handling overstriking in UTF-8 files.
295 * Fix some nroff issues in the man page.
297 ======================================================================
299 Major changes between "less" versions 376 and 378
302 Default buffer space is now 64K as documented.
303 Search highlighting works properly when used with -R.
304 Windows version works properly when input file contains carriage returns.
305 Clean up some compiler warnings.
307 ======================================================================
309 Major changes between "less" versions 358 and 376
311 * -x option can now specify multiple variable-width tab stops.
313 * -X option no longer disables keypad initialization.
314 New option --no-keypad disables keypad initialization.
316 * New commands t and T step through multiple tag matches.
317 Added support for "global(1)" tags
318 (see http://www.gnu.org/software/global/global.html).
320 * New prompt style set by option -Pw defines the message printed
321 while waiting for data in the F command.
323 * System-wide lesskey file now defaults to sysless in etc directory
324 instead of .sysless in bin directory.
325 Use "configure --sysconfdir=..." to change it.
326 (For backwards compatibility, .sysless in bin is still recognized.)
328 * Pressing RightArrow or LeftArrow while entering a number now shifts
329 the display N columns rather than editing the number itself.
331 * Status column (enabled with -J) now shows search results.
333 * Windows version sets window title.
335 * Default LESSCHARSET for MS-DOS versions is now "dos".
337 * Searching works better with ANSI (SGR) escape sequences.
338 ANSI color escape sequences are now supported in the MS-DOS (DJGPP) version.
340 * Improved performance in reading very large pipes.
342 * Eliminated some dependencies on file offets being 32 bits.
344 * Fixed problems when viewing files with very long lines.
346 * Fixed overstriking in UTF-8 mode, and overstriking tabs.
348 * Improved horizontal shifting of text using -R option with ANSI color.
350 * Improved handling of filenames containing shell metacharacters.
352 * Some fixes for EBCDIC systems.
354 * Some fixes for OS/2 systems.
356 ======================================================================
358 Major changes between "less" versions 354 and 358
360 * Add -J (--status-column) option to display a status column.
362 * Add -# (--shift) option to set default horizontal shift distance.
363 Default horizontal shift distance is now one-half screen width.
365 * Horizontal shifting does not shift line numbers if -N is in effect.
367 * Horizontal shifting acts as though -S were set, to avoid confusion.
369 ======================================================================
372 Major changes between "less" versions 352 and 354
374 * Allow space after numeric-valued command line options.
376 * Fix problem with configuring terminal libraries on some systems.
378 * Add support for PCRE regular expression library.
380 * Add --with-regex option to configure to allow manually selecting
381 a regular expression library.
383 * Fix bug compiling with SECURE = 1.
385 ======================================================================
388 Major changes between "less" versions 346 and 352
390 * Enable UTF-8 if "UTF-8" appears in locale-related environment variables.
392 * Add --with-editor option to configure script.
394 * The -M prompt and = message now show the top and bottom line number.
396 * Fix bug in running the editor on a file whose name contains quotes, etc.
398 * Fix bug in horizontal scrolling of long lines.
400 * Fix bug in doing :d on a file which contains marks.
402 * Fix bug causing cleared lines to sometimes be filled with standout,
403 bold, underline, etc. on certain terminals.
405 * Fixes for MS-DOS (DJGPP) version.
407 ======================================================================
410 Major changes between "less" versions 340 and 346
412 * The UTF-8 character set is now supported.
414 * The default character set is now latin1 rather than ascii.
416 * New option -R (--RAW-CONTROL-CHARS) is like -r but handles
417 long (wrapped) lines correctly, as long as the input contains only
418 normal text and ANSI color escape sequences.
420 * New option -F (--quit-if-one-screen) quits if the text fits on
423 * The -w option now highlights the target line of a g or p command.
425 * A system-wide lesskey file is supported (LESSKEY_SYSTEM).
427 * New escape for prompt strings: %c is replaced by column number.
429 * New escape for prompt strings: %P is replaced by percentage into
430 file, based on line number rather than byte offset.
432 * HOME and END keys now jump to beginning of file or end of file.
434 ======================================================================
437 Major changes between "less" versions 337 and 340
439 * Command line options for less may now be given in either the old
440 single-letter form, or a new long name form (--option-name).
441 See the less man page or "less --help" for the list of long option names.
443 * Command line options for lesskey may now be given in a new long name
444 form. See the lesskey man page for the list of long option names.
446 * New command -- toggles an option using the long option name.
448 * New command __ queries an option using the long option name.
450 * The old -- command is renamed as -!.
452 * If a ^P is entered between the dash and the option letter of the -
453 command, the message describing the new setting is suppressed.
455 * Lesskey files may now contain \k escape sequences to represent the
456 "special" keys (arrows, PAGE-UP/PAGE-DOWN, HOME, END, INSERT, DELETE).
458 * New command :d removes the current file from the list of files.
460 * New option -~ (like -w before version 335)
461 suppresses tildes after end-of-file.
463 * Less is now released under the GNU General Public License.
465 ======================================================================
468 Major changes between "less" versions 335 and 337
470 * Fixed bugs in "make install".
472 ======================================================================
475 Major changes between "less" versions 332 and 335
477 * The old -w flag (suppress tildes after end-of-file) has been removed.
479 * New -w flag highlights the first new line after a forward-screen.
481 * New -W flag highlights the first new line after any forward movement.
483 * Window resize works even if LINES and/or COLUMNS environment
484 variables are incorrect.
486 * New percent escapes for prompt strings:
487 %d is replaced by the page number, and
488 %D is replaced by the number of pages in the file.
490 * Added charsets "iso8859" and "ebcdic".
492 * In Windows version, uses HOMEDRIVE and HOMEPATH if HOME is not defined.
494 * Fixed some bugs causing incorrect display on DOS/Windows.
496 ======================================================================
499 Major changes between "less" versions 330 and 332
501 * Filenames from the command line are entered into the command history,
502 so UPARROW/DOWNARROW can be used to retrieve them from the :e command.
504 * Now works correctly on Windows when using a scrolling terminal
505 window (buffer larger than display window).
507 * On Windows, now restores the console screen on exit.
508 Use -X to get the old behavior.
510 * Fixed bug on Windows when CAPS-LOCK or NUM-LOCK is pressed.
512 * Fixed bug on Windows when piping output of an interactive program.
514 * Fixed bug in tags file processing when tags file has DOS-style
515 line terminators (CR/LF).
517 * Fixed compilation problem on OS/2.
519 ======================================================================
522 Major changes between "less" versions 321 and 330
524 * Now supports filenames containing spaces (in double quotes).
525 New option -" can be used to change the quoting characters.
527 * In filename completion, a slash is appended to a directory name.
528 If the environment variable LESSSEPARATOR is set, the value of
529 that variable, rather than a slash, is appended.
531 * LeftArrow and RightArrow are same as ESC-[ and ESC-].
533 * Added commands ESC-( and ESC-), same as ESC-[ and ESC-].
535 * A "quit" command defined in a lesskey file may now have an "extra"
536 string, which is used to return an exit code from less when it quits.
538 * New environment variables LESSMETACHARS and LESSMETAESCAPE provide
539 more control over how less interfaces to the shell.
541 * Ported to Microsoft Visual C compiler for Windows.
543 * Ported to DJGPP compiler for MS-DOS.
547 ======================================================================
550 Major changes between "less" versions 291 and 321
552 * Command line at bottom of screen now scrolls, so it can be longer
553 than the screen width.
555 * New commands ESC-] and ESC-[ scroll the display horizontally.
557 * New command ESC-SPACE scrolls forward a full screen, even if it
560 * Alternate modifiers for search commands: ^N is same as !,
561 ^F is same as @, and ^E is same as *.
563 * New modifier for search commands: ^K means highlight the matches
564 currently on-screen, but don't move to the first match.
566 * New modifier for search commands: ^R means don't use regular
567 expressions in the search.
569 * Environment variable LESSKEY gives name of default lesskey file.
571 * Environment variable LESSSECURE will force less to run in
574 * Command line argument "--" signals that the rest of the arguments
575 are files (not option flags).
577 * Help file (less.hlp) is no longer installed. Help text is now
578 embedded in the less executable itself.
580 * Added -Ph to change the prompt for the help text.
581 Added -Ps to change the default short prompt (same as plain -P).
583 * Ported to the Borland C compiler for MS-DOS.
585 * Ported to Windows 95 & Windows NT.
589 * Ported to GNU Hurd.
591 ======================================================================
594 Major changes between "less" versions 290 and 291
596 * Less environment variables can be specified in lesskey files.
598 * Fixed MS-DOS build.
600 ======================================================================
603 Major changes between "less" versions 278 and 290
605 * Accepts GNU-style options "--help" and "--version".
607 * OS/2 version looks for less.ini in $HOME before $INIT and $PATH.
611 ======================================================================
614 Major changes between "less" versions 252 and 278
616 * A LESSOPEN preprocessor may now pipe the converted file data to less,
617 rather than writing it to a temporary file.
619 * Search pattern highlighting has been fixed. It now highlights
620 reliably, even if a string is split across two screen lines,
623 * The -F flag (which suppress search highlighting) has been changed
624 to -G. A new flag, -g, changes search highlighting to highlight
625 only the string found by the last search command, instead of all
626 strings which match the last search command.
628 * New flag -I acts like -i, but ignores case even if the search
629 pattern contains uppercase letters.
631 * Less now checks for the environment variable VISUAL before EDITOR.
635 ======================================================================
638 Major changes between "less" versions 237 and 252
640 * Changes in line-editing keys:
641 The literal key is now ^V or ^A rather than \ (backslash).
642 Filename completion commands (TAB and ^L) are disabled
643 when typing a search pattern.
645 * Line-editing command keys can be redefined using lesskey.
647 * Lesskey with no input file defaults to $HOME/.lesskey
648 rather than standard input.
650 * New option -V displays version number of less.
652 * New option -V displays version number of lesskey.
654 * Help file less.hlp is now installed by default in /usr/local/share
655 rather than /usr/local/lib.
658 ======================================================================
661 Major changes between "less" versions 170 and 237
663 * By popular demand, text which matches the current search pattern
664 is highlighted. New -F flag disables this feature.
666 * Henry Spencer's regexp.c is now included, for systems which do not
667 have a regular expression library.
668 regexp.c is Copyright (c) 1986 by University of Toronto.
670 * New line-editing keys, including command history (arrow keys) and
671 filename completion (TAB).
673 * Input preprocessor allows modification of input files (e.g. uncompress)
674 via LESSOPEN/LESSCLOSE environment variables.
676 * New -X flag disables sending termcap "ti" and "te" (initialize and
677 deinitialize) strings to the terminal.
679 * Changing -i from within less now correctly affects a subsequent
682 * Searching for underlined or overstruck text now works when the -u
683 flag is in effect, rather than the -i flag.
685 * Use setlocale (LANG and LC_CTYPE environment variables) to determine
686 the character set if LESSCHARSET/LESSCHARDEF are not set.
688 * The default format for displaying binary characters is now standout
689 (reverse video) rather than blinking. This can still be changed by
690 setting the LESSBINFMT environment variable.
692 * Use autoconf installation technology.
696 ********************************
697 Things that may surprise you
698 ********************************
700 * When you enter text at the bottom of the screen (search string,
701 filename, etc.), some keys act different than previously.
702 Specifically, \ (backslash), ESC, TAB, BACKTAB, and control-L
703 now have line editing functions.
705 * Some previous unofficial versions of less were able to display
706 compressed files. The new LESSOPEN/LESSCLOSE feature now provides
707 this functionality in a different way.
709 * Some previous unofficial versions of less provided a -Z flag to
710 set the number of lines of text to retain between full screen scrolls.
711 The -z-n flag (that is, -z with a negative number) provides this
715 ======================================================================
718 Major changes between "less" versions 123 and 170
720 * New option -j allows target lines to be positioned anywhere on screen.
722 * New option -S truncates displayed line at the screen width,
723 rather than wrapping onto the next line.
725 * New option -y limits amount of forward scroll.
727 * New option -T specifies a "tags" file.
729 * Non-printable, non-control characters are displayed in octal.
730 Such characters, as well as control characters, are displayed
733 * New command -+ sets an option to its default.
734 * New command -- sets an option to the opposite of its default.
736 * Lesskey file may have a string appended to a key's action,
737 which acts as though typed in after the command.
739 * New commands ESC-^F and ESC-^B match arbitrary types of brackets.
741 * New command F monitors a growing file (like "tail -f").
743 * New command | pipes a section of the input file into a shell command.
745 * New command :x directly jumps to a file in the command line list.
747 * Search commands have been enhanced and reorganized:
748 n Repeat search, same direction.
749 N Repeat search, opposite direction.
750 ESC-/ Search forward thru file boundaries
751 ESC-? Search backward thru file boundaries
752 ESC-n Repeat search thru file boundaries, same direction.
753 ESC-N Repeat search thru file boundaries, opposite direction.
754 Special character * causes search to search thru file boundaries.
755 Special character @ causes search to begin at start/end of file list.
757 * Examining a new file adds it to the command line list.
758 A list of files, or an expression which matches more than one file,
759 may be examined; all of them are added to the command line list.
761 * Environment variables LESSCHARSET and LESSCHARDEF can define
762 a non-ASCII character set.
764 * Partial support for MSDOS, including options -R for repainting screen
765 on quit, -v/-V to select video mode, and -W to change window size.
768 ======================================================================
771 Major changes between "less" versions 97 and 123
773 * New option (-N) causes line numbers to be displayed in the
774 text of the file (like vi "set nu").
776 * New option (-?) prints help message immediately.
778 * New option (-r) displays "raw" control characters, without
779 mapping them to ^X notation.
781 * New option (-f) forces less to open non-regular files
784 * New option (-k) can be used to specify lesskey files by name.
786 * New option (-y) can be used to set a forward scroll limit
787 (like -h sets a backward scroll limit).
789 * File marks (set by the m command) are now preserved when a new
790 file is edited. The ' command can thus be used to switch files.
792 * New command ESC-/ searches all files (on the command line)
795 * New command ESC-n repeats previous search, spanning files.
797 * The N command has been changed to repeat the previous search
798 in the reverse direction. The old N command is still available
801 * New command ESC-N repeats previous search in the reverse
802 direction and spanning files.
804 * 8 bit characters are now supported. A new option (-g) can be
805 used to strip off the eighth bit (the previous behavior).
807 * Options which take a following string (like -t) may now
808 optionally have a space between the option letter and the string.
810 * Six new commands { } ( ) [ and ] can be used to match
811 brackets of specific types, similar to vi % command.
813 * New commands z and w move forward/backward one window and
814 simultaneously set the window size.
816 * Prompt string expansion now has %L for line number of the last
817 line in the file, and %E for the name of the editor.
818 Also, % escapes which refer to a line (b=bottom, t=top, etc.)
819 can use j for the jump target line.
821 * New environment variable LESSEDIT can be used to tailor the
822 command string passed to the editor by the v command.
824 * Examining a file which was previously examined will return
825 to the same position in the file.
827 * A "%" is expanded to the current filename and a "#" to the
828 previous filename, in both shell commands and the E command.
829 (Previously % worked only in shell commands and # worked
830 only in the E command.)
832 * New command ":ta" is equivalent to "-t".
834 * New command "s" is equivalent to "-l".
836 * The - command may be followed by "+X" to revert to the default
837 for option X, or "-X" to get the opposite of the default.
839 * Lesskey files may now include characters after the action as
840 extra input to be parsed after the action; for example:
841 "toggle-option X" to toggle a specific option X.