less.man revision 170964
1LESS(1) LESS(1) 2 3 4 5[1mNAME[0m 6 less - opposite of more 7 8[1mSYNOPSIS[0m 9 [1mless -?[0m 10 [1mless --help[0m 11 [1mless -V[0m 12 [1mless --version[0m 13 [1mless [-[+]aBcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~][0m 14 [1m[-b [4m[22mspace[24m[1m] [-h [4m[22mlines[24m[1m] [-j [4m[22mline[24m[1m] [-k [4m[22mkeyfile[24m[1m][0m 15 [1m[-{oO} [4m[22mlogfile[24m[1m] [-p [4m[22mpattern[24m[1m] [-P [4m[22mprompt[24m[1m] [-t [4m[22mtag[24m[1m][0m 16 [1m[-T [4m[22mtagsfile[24m[1m] [-x [4m[22mtab[24m[1m,...] [-y [4m[22mlines[24m[1m] [-[z] [4m[22mlines[24m[1m][0m 17 [1m[-# [4m[22mshift[24m[1m] [+[+][4m[22mcmd[24m[1m] [--] [[4m[22mfilename[24m[1m]...[0m 18 (See the OPTIONS section for alternate option syntax with long option 19 names.) 20 21 22[1mDESCRIPTION[0m 23 [4mLess[24m is a program similar to [4mmore[24m (1), but which allows backward move- 24 ment in the file as well as forward movement. Also, [4mless[24m does not have 25 to read the entire input file before starting, so with large input 26 files it starts up faster than text editors like [4mvi[24m (1). [4mLess[24m uses 27 termcap (or terminfo on some systems), so it can run on a variety of 28 terminals. There is even limited support for hardcopy terminals. (On 29 a hardcopy terminal, lines which should be printed at the top of the 30 screen are prefixed with a caret.) 31 32 Commands are based on both [4mmore[24m and [4mvi.[24m Commands may be preceded by a 33 decimal number, called N in the descriptions below. The number is used 34 by some commands, as indicated. 35 36 37[1mCOMMANDS[0m 38 In the following descriptions, ^X means control-X. ESC stands for the 39 ESCAPE key; for example ESC-v means the two character sequence 40 "ESCAPE", then "v". 41 42 h or H Help: display a summary of these commands. If you forget all 43 the other commands, remember this one. 44 45 SPACE or ^V or f or ^F 46 Scroll forward N lines, default one window (see option -z 47 below). If N is more than the screen size, only the final 48 screenful is displayed. Warning: some systems use ^V as a spe- 49 cial literalization character. 50 51 z Like SPACE, but if N is specified, it becomes the new window 52 size. 53 54 ESC-SPACE 55 Like SPACE, but scrolls a full screenful, even if it reaches 56 end-of-file in the process. 57 58 RETURN or ^N or e or ^E or j or ^J 59 Scroll forward N lines, default 1. The entire N lines are dis- 60 played, even if N is more than the screen size. 61 62 d or ^D 63 Scroll forward N lines, default one half of the screen size. If 64 N is specified, it becomes the new default for subsequent d and 65 u commands. 66 67 b or ^B or ESC-v 68 Scroll backward N lines, default one window (see option -z 69 below). If N is more than the screen size, only the final 70 screenful is displayed. 71 72 w Like ESC-v, but if N is specified, it becomes the new window 73 size. 74 75 y or ^Y or ^P or k or ^K 76 Scroll backward N lines, default 1. The entire N lines are dis- 77 played, even if N is more than the screen size. Warning: some 78 systems use ^Y as a special job control character. 79 80 u or ^U 81 Scroll backward N lines, default one half of the screen size. 82 If N is specified, it becomes the new default for subsequent d 83 and u commands. 84 85 ESC-) or RIGHTARROW 86 Scroll horizontally right N characters, default half the screen 87 width (see the -# option). If a number N is specified, it 88 becomes the default for future RIGHTARROW and LEFTARROW com- 89 mands. While the text is scrolled, it acts as though the -S 90 option (chop lines) were in effect. 91 92 ESC-( or LEFTARROW 93 Scroll horizontally left N characters, default half the screen 94 width (see the -# option). If a number N is specified, it 95 becomes the default for future RIGHTARROW and LEFTARROW com- 96 mands. 97 98 r or ^R or ^L 99 Repaint the screen. 100 101 R Repaint the screen, discarding any buffered input. Useful if 102 the file is changing while it is being viewed. 103 104 F Scroll forward, and keep trying to read when the end of file is 105 reached. Normally this command would be used when already at 106 the end of the file. It is a way to monitor the tail of a file 107 which is growing while it is being viewed. (The behavior is 108 similar to the "tail -f" command.) 109 110 g or < or ESC-< 111 Go to line N in the file, default 1 (beginning of file). (Warn- 112 ing: this may be slow if N is large.) 113 114 G or > or ESC-> 115 Go to line N in the file, default the end of the file. (Warn- 116 ing: this may be slow if N is large, or if N is not specified 117 and standard input, rather than a file, is being read.) 118 119 p or % Go to a position N percent into the file. N should be between 0 120 and 100, and may contain a decimal point. 121 122 P Go to the line containing byte offset N in the file. 123 124 { If a left curly bracket appears in the top line displayed on the 125 screen, the { command will go to the matching right curly 126 bracket. The matching right curly bracket is positioned on the 127 bottom line of the screen. If there is more than one left curly 128 bracket on the top line, a number N may be used to specify the 129 N-th bracket on the line. 130 131 } If a right curly bracket appears in the bottom line displayed on 132 the screen, the } command will go to the matching left curly 133 bracket. The matching left curly bracket is positioned on the 134 top line of the screen. If there is more than one right curly 135 bracket on the top line, a number N may be used to specify the 136 N-th bracket on the line. 137 138 ( Like {, but applies to parentheses rather than curly brackets. 139 140 ) Like }, but applies to parentheses rather than curly brackets. 141 142 [ Like {, but applies to square brackets rather than curly brack- 143 ets. 144 145 ] Like }, but applies to square brackets rather than curly brack- 146 ets. 147 148 ESC-^F Followed by two characters, acts like {, but uses the two char- 149 acters as open and close brackets, respectively. For example, 150 "ESC ^F < >" could be used to go forward to the > which matches 151 the < in the top displayed line. 152 153 ESC-^B Followed by two characters, acts like }, but uses the two char- 154 acters as open and close brackets, respectively. For example, 155 "ESC ^B < >" could be used to go backward to the < which matches 156 the > in the bottom displayed line. 157 158 m Followed by any lowercase letter, marks the current position 159 with that letter. 160 161 ' (Single quote.) Followed by any lowercase letter, returns to 162 the position which was previously marked with that letter. Fol- 163 lowed by another single quote, returns to the position at which 164 the last "large" movement command was executed. Followed by a ^ 165 or $, jumps to the beginning or end of the file respectively. 166 Marks are preserved when a new file is examined, so the ' com- 167 mand can be used to switch between input files. 168 169 ^X^X Same as single quote. 170 171 /pattern 172 Search forward in the file for the N-th line containing the pat- 173 tern. N defaults to 1. The pattern is a regular expression, as 174 recognized by the regular expression library supplied by your 175 system. The search starts at the second line displayed (but see 176 the -a and -j options, which change this). 177 178 Certain characters are special if entered at the beginning of 179 the pattern; they modify the type of search rather than become 180 part of the pattern: 181 182 ^N or ! 183 Search for lines which do NOT match the pattern. 184 185 ^E or * 186 Search multiple files. That is, if the search reaches 187 the END of the current file without finding a match, the 188 search continues in the next file in the command line 189 list. 190 191 ^F or @ 192 Begin the search at the first line of the FIRST file in 193 the command line list, regardless of what is currently 194 displayed on the screen or the settings of the -a or -j 195 options. 196 197 ^K Highlight any text which matches the pattern on the cur- 198 rent screen, but don't move to the first match (KEEP 199 current position). 200 201 ^R Don't interpret regular expression metacharacters; that 202 is, do a simple textual comparison. 203 204 ?pattern 205 Search backward in the file for the N-th line containing the 206 pattern. The search starts at the line immediately before the 207 top line displayed. 208 209 Certain characters are special as in the / command: 210 211 ^N or ! 212 Search for lines which do NOT match the pattern. 213 214 ^E or * 215 Search multiple files. That is, if the search reaches 216 the beginning of the current file without finding a 217 match, the search continues in the previous file in the 218 command line list. 219 220 ^F or @ 221 Begin the search at the last line of the last file in the 222 command line list, regardless of what is currently dis- 223 played on the screen or the settings of the -a or -j 224 options. 225 226 ^K As in forward searches. 227 228 ^R As in forward searches. 229 230 ESC-/pattern 231 Same as "/*". 232 233 ESC-?pattern 234 Same as "?*". 235 236 n Repeat previous search, for N-th line containing the last pat- 237 tern. If the previous search was modified by ^N, the search is 238 made for the N-th line NOT containing the pattern. If the pre- 239 vious search was modified by ^E, the search continues in the 240 next (or previous) file if not satisfied in the current file. 241 If the previous search was modified by ^R, the search is done 242 without using regular expressions. There is no effect if the 243 previous search was modified by ^F or ^K. 244 245 N Repeat previous search, but in the reverse direction. 246 247 ESC-n Repeat previous search, but crossing file boundaries. The 248 effect is as if the previous search were modified by *. 249 250 ESC-N Repeat previous search, but in the reverse direction and cross- 251 ing file boundaries. 252 253 ESC-u Undo search highlighting. Turn off highlighting of strings 254 matching the current search pattern. If highlighting is already 255 off because of a previous ESC-u command, turn highlighting back 256 on. Any search command will also turn highlighting back on. 257 (Highlighting can also be disabled by toggling the -G option; in 258 that case search commands do not turn highlighting back on.) 259 260 :e [filename] 261 Examine a new file. If the filename is missing, the "current" 262 file (see the :n and :p commands below) from the list of files 263 in the command line is re-examined. A percent sign (%) in the 264 filename is replaced by the name of the current file. A pound 265 sign (#) is replaced by the name of the previously examined 266 file. However, two consecutive percent signs are simply 267 replaced with a single percent sign. This allows you to enter a 268 filename that contains a percent sign in the name. Similarly, 269 two consecutive pound signs are replaced with a single pound 270 sign. The filename is inserted into the command line list of 271 files so that it can be seen by subsequent :n and :p commands. 272 If the filename consists of several files, they are all inserted 273 into the list of files and the first one is examined. If the 274 filename contains one or more spaces, the entire filename should 275 be enclosed in double quotes (also see the -" option). 276 277 ^X^V or E 278 Same as :e. Warning: some systems use ^V as a special literal- 279 ization character. On such systems, you may not be able to use 280 ^V. 281 282 :n Examine the next file (from the list of files given in the com- 283 mand line). If a number N is specified, the N-th next file is 284 examined. 285 286 :p Examine the previous file in the command line list. If a number 287 N is specified, the N-th previous file is examined. 288 289 :x Examine the first file in the command line list. If a number N 290 is specified, the N-th file in the list is examined. 291 292 :d Remove the current file from the list of files. 293 294 t Go to the next tag, if there were more than one matches for the 295 current tag. See the -t option for more details about tags. 296 297 T Go to the previous tag, if there were more than one matches for 298 the current tag. 299 300 = or ^G or :f 301 Prints some information about the file being viewed, including 302 its name and the line number and byte offset of the bottom line 303 being displayed. If possible, it also prints the length of the 304 file, the number of lines in the file and the percent of the 305 file above the last displayed line. 306 307 - Followed by one of the command line option letters (see OPTIONS 308 below), this will change the setting of that option and print a 309 message describing the new setting. If a ^P (CONTROL-P) is 310 entered immediately after the dash, the setting of the option is 311 changed but no message is printed. If the option letter has a 312 numeric value (such as -b or -h), or a string value (such as -P 313 or -t), a new value may be entered after the option letter. If 314 no new value is entered, a message describing the current set- 315 ting is printed and nothing is changed. 316 317 -- Like the - command, but takes a long option name (see OPTIONS 318 below) rather than a single option letter. You must press 319 RETURN after typing the option name. A ^P immediately after the 320 second dash suppresses printing of a message describing the new 321 setting, as in the - command. 322 323 -+ Followed by one of the command line option letters this will 324 reset the option to its default setting and print a message 325 describing the new setting. (The "-+[4mX[24m" command does the same 326 thing as "-+[4mX[24m" on the command line.) This does not work for 327 string-valued options. 328 329 --+ Like the -+ command, but takes a long option name rather than a 330 single option letter. 331 332 -! Followed by one of the command line option letters, this will 333 reset the option to the "opposite" of its default setting and 334 print a message describing the new setting. This does not work 335 for numeric or string-valued options. 336 337 --! Like the -! command, but takes a long option name rather than a 338 single option letter. 339 340 _ (Underscore.) Followed by one of the command line option let- 341 ters, this will print a message describing the current setting 342 of that option. The setting of the option is not changed. 343 344 __ (Double underscore.) Like the _ (underscore) command, but takes 345 a long option name rather than a single option letter. You must 346 press RETURN after typing the option name. 347 348 +cmd Causes the specified cmd to be executed each time a new file is 349 examined. For example, +G causes [4mless[24m to initially display each 350 file starting at the end rather than the beginning. 351 352 V Prints the version number of [4mless[24m being run. 353 354 q or Q or :q or :Q or ZZ 355 Exits [4mless.[0m 356 357 The following four commands may or may not be valid, depending on your 358 particular installation. 359 360 361 v Invokes an editor to edit the current file being viewed. The 362 editor is taken from the environment variable VISUAL if defined, 363 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei- 364 ther VISUAL nor EDITOR is defined. See also the discussion of 365 LESSEDIT under the section on PROMPTS below. 366 367 ! shell-command 368 Invokes a shell to run the shell-command given. A percent sign 369 (%) in the command is replaced by the name of the current file. 370 A pound sign (#) is replaced by the name of the previously exam- 371 ined file. "!!" repeats the last shell command. "!" with no 372 shell command simply invokes a shell. On Unix systems, the 373 shell is taken from the environment variable SHELL, or defaults 374 to "sh". On MS-DOS and OS/2 systems, the shell is the normal 375 command processor. 376 377 | <m> shell-command 378 <m> represents any mark letter. Pipes a section of the input 379 file to the given shell command. The section of the file to be 380 piped is between the first line on the current screen and the 381 position marked by the letter. <m> may also be ^ or $ to indi- 382 cate beginning or end of file respectively. If <m> is . or new- 383 line, the current screen is piped. 384 385 s filename 386 Save the input to a file. This only works if the input is a 387 pipe, not an ordinary file. 388 389 390[1mOPTIONS[0m 391 Command line options are described below. Most options may be changed 392 while [4mless[24m is running, via the "-" command. 393 394 Most options may be given in one of two forms: either a dash followed 395 by a single letter, or two dashes followed by a long option name. A 396 long option name may be abbreviated as long as the abbreviation is 397 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but 398 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some 399 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct 400 from --quit-at-eof. Such option names need only have their first let- 401 ter capitalized; the remainder of the name may be in either case. For 402 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF. 403 404 Options are also taken from the environment variable "LESS". For exam- 405 ple, to avoid typing "less -options ..." each time [4mless[24m is invoked, you 406 might tell [4mcsh:[0m 407 408 setenv LESS "-options" 409 410 or if you use [4msh:[0m 411 412 LESS="-options"; export LESS 413 414 On MS-DOS, you don't need the quotes, but you should replace any per- 415 cent signs in the options string by double percent signs. 416 417 The environment variable is parsed before the command line, so command 418 line options override the LESS environment variable. If an option 419 appears in the LESS variable, it can be reset to its default value on 420 the command line by beginning the command line option with "-+". 421 422 For options like -P or -D which take a following string, a dollar sign 423 ($) must be used to signal the end of the string. For example, to set 424 two -D options on MS-DOS, you must have a dollar sign between them, 425 like this: 426 427 LESS="-Dn9.1$-Ds4.1" 428 429 430 -? or --help 431 This option displays a summary of the commands accepted by [4mless[0m 432 (the same as the h command). (Depending on how your shell 433 interprets the question mark, it may be necessary to quote the 434 question mark, thus: "-\?".) 435 436 -a or --search-skip-screen 437 Causes searches to start after the last line displayed on the 438 screen, thus skipping all lines displayed on the screen. By 439 default, searches start at the second line on the screen (or 440 after the last found line; see the -j option). 441 442 -b[4mn[24m or --buffers=[4mn[0m 443 Specifies the amount of buffer space [4mless[24m will use for each 444 file, in units of kilobytes (1024 bytes). By default 64K of 445 buffer space is used for each file (unless the file is a pipe; 446 see the -B option). The -b option specifies instead that [4mn[0m 447 kilobytes of buffer space should be used for each file. If [4mn[24m is 448 -1, buffer space is unlimited; that is, the entire file is read 449 into memory. 450 451 -B or --auto-buffers 452 By default, when data is read from a pipe, buffers are allocated 453 automatically as needed. If a large amount of data is read from 454 the pipe, this can cause a large amount of memory to be allo- 455 cated. The -B option disables this automatic allocation of 456 buffers for pipes, so that only 64K (or the amount of space 457 specified by the -b option) is used for the pipe. Warning: use 458 of -B can result in erroneous display, since only the most 459 recently viewed part of the file is kept in memory; any earlier 460 data is lost. 461 462 -c or --clear-screen 463 Causes full screen repaints to be painted from the top line 464 down. By default, full screen repaints are done by scrolling 465 from the bottom of the screen. 466 467 -C or --CLEAR-SCREEN 468 Same as -c, for compatibility with older versions of [4mless.[0m 469 470 -d or --dumb 471 The -d option suppresses the error message normally displayed if 472 the terminal is dumb; that is, lacks some important capability, 473 such as the ability to clear the screen or scroll backward. The 474 -d option does not otherwise change the behavior of [4mless[24m on a 475 dumb terminal. 476 477 -D[1mx[4m[22mcolor[24m or --color=[1mx[4m[22mcolor[0m 478 [MS-DOS only] Sets the color of the text displayed. [1mx [22mis a sin- 479 gle character which selects the type of text whose color is 480 being set: n=normal, s=standout, d=bold, u=underlined, k=blink. 481 [4mcolor[24m is a pair of numbers separated by a period. The first 482 number selects the foreground color and the second selects the 483 background color of the text. A single number [4mN[24m is the same as 484 [4mN.0[24m. 485 486 -e or --quit-at-eof 487 Causes [4mless[24m to automatically exit the second time it reaches 488 end-of-file. By default, the only way to exit [4mless[24m is via the 489 "q" command. 490 491 -E or --QUIT-AT-EOF 492 Causes [4mless[24m to automatically exit the first time it reaches end- 493 of-file. 494 495 -f or --force 496 Forces non-regular files to be opened. (A non-regular file is a 497 directory or a device special file.) Also suppresses the warn- 498 ing message when a binary file is opened. By default, [4mless[24m will 499 refuse to open non-regular files. Note that some operating sys- 500 tems will not allow directories to be read, even if -f is set. 501 502 -F or --quit-if-one-screen 503 Causes [4mless[24m to automatically exit if the entire file can be dis- 504 played on the first screen. 505 506 -g or --hilite-search 507 Normally, [4mless[24m will highlight ALL strings which match the last 508 search command. The -g option changes this behavior to high- 509 light only the particular string which was found by the last 510 search command. This can cause [4mless[24m to run somewhat faster than 511 the default. 512 513 -G or --HILITE-SEARCH 514 The -G option suppresses all highlighting of strings found by 515 search commands. 516 517 -h[4mn[24m or --max-back-scroll=[4mn[0m 518 Specifies a maximum number of lines to scroll backward. If it 519 is necessary to scroll backward more than [4mn[24m lines, the screen is 520 repainted in a forward direction instead. (If the terminal does 521 not have the ability to scroll backward, -h0 is implied.) 522 523 -i or --ignore-case 524 Causes searches to ignore case; that is, uppercase and lowercase 525 are considered identical. This option is ignored if any upper- 526 case letters appear in the search pattern; in other words, if a 527 pattern contains uppercase letters, then that search does not 528 ignore case. 529 530 -I or --IGNORE-CASE 531 Like -i, but searches ignore case even if the pattern contains 532 uppercase letters. 533 534 -j[4mn[24m or --jump-target=[4mn[0m 535 Specifies a line on the screen where the "target" line is to be 536 positioned. A target line is the object of a text search, tag 537 search, jump to a line number, jump to a file percentage, or 538 jump to a marked position. The screen line may be specified by 539 a number: the top line on the screen is 1, the next is 2, and so 540 on. The number may be negative to specify a line relative to 541 the bottom of the screen: the bottom line on the screen is -1, 542 the second to the bottom is -2, and so on. Alternately, the 543 screen line may be specified as a fraction of the height of the 544 screen, starting with a decimal point: .5 is in the middle of 545 the screen, .3 is three tenths down from the first line, and so 546 on. If the line is specified as a fraction, the actual line 547 number is recalculated if the terminal window is resized, so 548 that the target line remains at the specified fraction of the 549 screen height. If the -j option is used, searches begin at the 550 line immediately after the target line. For example, if "-j4" 551 is used, the target line is the fourth line on the screen, so 552 searches begin at the fifth line on the screen. 553 554 -J or --status-column 555 Displays a status column at the left edge of the screen. The 556 status column shows the lines that matched the current search. 557 The status column is also used if the -w or -W option is in 558 effect. 559 560 -k[4mfilename[24m or --lesskey-file=[4mfilename[0m 561 Causes [4mless[24m to open and interpret the named file as a [4mlesskey[0m 562 (1) file. Multiple -k options may be specified. If the LESSKEY 563 or LESSKEY_SYSTEM environment variable is set, or if a lesskey 564 file is found in a standard place (see KEY BINDINGS), it is also 565 used as a [4mlesskey[24m file. 566 567 -K or --quit-on-intr 568 Causes [4mless[24m to exit immediately when an interrupt character 569 (usually ^C) is typed. Normally, an interrupt character causes 570 [4mless[24m to stop whatever it is doing and return to its command 571 prompt. 572 573 -L or --no-lessopen 574 Ignore the LESSOPEN environment variable (see the INPUT PREPRO- 575 CESSOR section below). This option can be set from within [4mless[24m, 576 but it will apply only to files opened subsequently, not to the 577 file which is currently open. 578 579 -m or --long-prompt 580 Causes [4mless[24m to prompt verbosely (like [4mmore[24m), with the percent 581 into the file. By default, [4mless[24m prompts with a colon. 582 583 -M or --LONG-PROMPT 584 Causes [4mless[24m to prompt even more verbosely than [4mmore.[0m 585 586 -n or --line-numbers 587 Suppresses line numbers. The default (to use line numbers) may 588 cause [4mless[24m to run more slowly in some cases, especially with a 589 very large input file. Suppressing line numbers with the -n 590 option will avoid this problem. Using line numbers means: the 591 line number will be displayed in the verbose prompt and in the = 592 command, and the v command will pass the current line number to 593 the editor (see also the discussion of LESSEDIT in PROMPTS 594 below). 595 596 -N or --LINE-NUMBERS 597 Causes a line number to be displayed at the beginning of each 598 line in the display. 599 600 -o[4mfilename[24m or --log-file=[4mfilename[0m 601 Causes [4mless[24m to copy its input to the named file as it is being 602 viewed. This applies only when the input file is a pipe, not an 603 ordinary file. If the file already exists, [4mless[24m will ask for 604 confirmation before overwriting it. 605 606 -O[4mfilename[24m or --LOG-FILE=[4mfilename[0m 607 The -O option is like -o, but it will overwrite an existing file 608 without asking for confirmation. 609 610 If no log file has been specified, the -o and -O options can be 611 used from within [4mless[24m to specify a log file. Without a file 612 name, they will simply report the name of the log file. The "s" 613 command is equivalent to specifying -o from within [4mless.[0m 614 615 -p[4mpattern[24m or --pattern=[4mpattern[0m 616 The -p option on the command line is equivalent to specifying 617 +/[4mpattern[24m; that is, it tells [4mless[24m to start at the first occur- 618 rence of [4mpattern[24m in the file. 619 620 -P[4mprompt[24m or --prompt=[4mprompt[0m 621 Provides a way to tailor the three prompt styles to your own 622 preference. This option would normally be put in the LESS envi- 623 ronment variable, rather than being typed in with each [4mless[24m com- 624 mand. Such an option must either be the last option in the LESS 625 variable, or be terminated by a dollar sign. -Ps followed by a 626 string changes the default (short) prompt to that string. -Pm 627 changes the medium (-m) prompt. -PM changes the long (-M) 628 prompt. -Ph changes the prompt for the help screen. -P= 629 changes the message printed by the = command. -Pw changes the 630 message printed while waiting for data (in the F command). All 631 prompt strings consist of a sequence of letters and special 632 escape sequences. See the section on PROMPTS for more details. 633 634 -q or --quiet or --silent 635 Causes moderately "quiet" operation: the terminal bell is not 636 rung if an attempt is made to scroll past the end of the file or 637 before the beginning of the file. If the terminal has a "visual 638 bell", it is used instead. The bell will be rung on certain 639 other errors, such as typing an invalid character. The default 640 is to ring the terminal bell in all such cases. 641 642 -Q or --QUIET or --SILENT 643 Causes totally "quiet" operation: the terminal bell is never 644 rung. 645 646 -r or --raw-control-chars 647 Causes "raw" control characters to be displayed. The default is 648 to display control characters using the caret notation; for 649 example, a control-A (octal 001) is displayed as "^A". Warning: 650 when the -r option is used, [4mless[24m cannot keep track of the actual 651 appearance of the screen (since this depends on how the screen 652 responds to each type of control character). Thus, various dis- 653 play problems may result, such as long lines being split in the 654 wrong place. 655 656 -R or --RAW-CONTROL-CHARS 657 Like -r, but only ANSI "color" escape sequences are output in 658 "raw" form. Unlike -r, the screen appearance is maintained cor- 659 rectly in most cases. ANSI "color" escape sequences are 660 sequences of the form: 661 662 ESC [ ... m 663 664 where the "..." is zero or more color specification characters 665 For the purpose of keeping track of screen appearance, ANSI 666 color escape sequences are assumed to not move the cursor. You 667 can make [4mless[24m think that characters other than "m" can end ANSI 668 color escape sequences by setting the environment variable 669 LESSANSIENDCHARS to the list of characters which can end a color 670 escape sequence. And you can make [4mless[24m think that characters 671 other than the standard ones may appear between the ESC and the 672 m by setting the environment variable LESSANSIMIDCHARS to the 673 list of characters which can appear. 674 675 -s or --squeeze-blank-lines 676 Causes consecutive blank lines to be squeezed into a single 677 blank line. This is useful when viewing [4mnroff[24m output. 678 679 -S or --chop-long-lines 680 Causes lines longer than the screen width to be chopped rather 681 than folded. That is, the portion of a long line that does not 682 fit in the screen width is not shown. The default is to fold 683 long lines; that is, display the remainder on the next line. 684 685 -t[4mtag[24m or --tag=[4mtag[0m 686 The -t option, followed immediately by a TAG, will edit the file 687 containing that tag. For this to work, tag information must be 688 available; for example, there may be a file in the current 689 directory called "tags", which was previously built by [4mctags[24m (1) 690 or an equivalent command. If the environment variable LESSGLOB- 691 ALTAGS is set, it is taken to be the name of a command compati- 692 ble with [4mglobal[24m (1), and that command is executed to find the 693 tag. (See http://www.gnu.org/software/global/global.html). The 694 -t option may also be specified from within [4mless[24m (using the - 695 command) as a way of examining a new file. The command ":t" is 696 equivalent to specifying -t from within [4mless.[0m 697 698 -T[4mtagsfile[24m or --tag-file=[4mtagsfile[0m 699 Specifies a tags file to be used instead of "tags". 700 701 -u or --underline-special 702 Causes backspaces and carriage returns to be treated as print- 703 able characters; that is, they are sent to the terminal when 704 they appear in the input. 705 706 -U or --UNDERLINE-SPECIAL 707 Causes backspaces, tabs and carriage returns to be treated as 708 control characters; that is, they are handled as specified by 709 the -r option. 710 711 By default, if neither -u nor -U is given, backspaces which 712 appear adjacent to an underscore character are treated spe- 713 cially: the underlined text is displayed using the terminal's 714 hardware underlining capability. Also, backspaces which appear 715 between two identical characters are treated specially: the 716 overstruck text is printed using the terminal's hardware bold- 717 face capability. Other backspaces are deleted, along with the 718 preceding character. Carriage returns immediately followed by a 719 newline are deleted. other carriage returns are handled as 720 specified by the -r option. Text which is overstruck or under- 721 lined can be searched for if neither -u nor -U is in effect. 722 723 -V or --version 724 Displays the version number of [4mless.[0m 725 726 -w or --hilite-unread 727 Temporarily highlights the first "new" line after a forward 728 movement of a full page. The first "new" line is the line imme- 729 diately following the line previously at the bottom of the 730 screen. Also highlights the target line after a g or p command. 731 The highlight is removed at the next command which causes move- 732 ment. The entire line is highlighted, unless the -J option is 733 in effect, in which case only the status column is highlighted. 734 735 -W or --HILITE-UNREAD 736 Like -w, but temporarily highlights the first new line after any 737 forward movement command larger than one line. 738 739 -x[4mn[24m,... or --tabs=[4mn[24m,... 740 Sets tab stops. If only one [4mn[24m is specified, tab stops are set 741 at multiples of [4mn[24m. If multiple values separated by commas are 742 specified, tab stops are set at those positions, and then 743 continue with the same spacing as the last two. For example, 744 [4m-x9,17[24m will set tabs at positions 9, 17, 25, 33, etc. The 745 default for [4mn[24m is 8. 746 747 -X or --no-init 748 Disables sending the termcap initialization and deinitialization 749 strings to the terminal. This is sometimes desirable if the 750 deinitialization string does something unnecessary, like clear- 751 ing the screen. 752 753 --no-keypad 754 Disables sending the keypad initialization and deinitialization 755 strings to the terminal. This is sometimes useful if the keypad 756 strings make the numeric keypad behave in an undesirable manner. 757 758 -y[4mn[24m or --max-forw-scroll=[4mn[0m 759 Specifies a maximum number of lines to scroll forward. If it is 760 necessary to scroll forward more than [4mn[24m lines, the screen is 761 repainted instead. The -c or -C option may be used to repaint 762 from the top of the screen if desired. By default, any forward 763 movement causes scrolling. 764 765 -[z][4mn[24m or --window=[4mn[0m 766 Changes the default scrolling window size to [4mn[24m lines. The 767 default is one screenful. The z and w commands can also be used 768 to change the window size. The "z" may be omitted for compati- 769 bility with some versions of [4mmore.[24m If the number [4mn[24m is negative, 770 it indicates [4mn[24m lines less than the current screen size. For 771 example, if the screen is 24 lines, [4m-z-4[24m sets the scrolling win- 772 dow to 20 lines. If the screen is resized to 40 lines, the 773 scrolling window automatically changes to 36 lines. 774 775 -[4m"cc[24m or --quotes=[4mcc[0m 776 Changes the filename quoting character. This may be necessary 777 if you are trying to name a file which contains both spaces and 778 quote characters. Followed by a single character, this changes 779 the quote character to that character. Filenames containing a 780 space should then be surrounded by that character rather than by 781 double quotes. Followed by two characters, changes the open 782 quote to the first character, and the close quote to the second 783 character. Filenames containing a space should then be preceded 784 by the open quote character and followed by the close quote 785 character. Note that even after the quote characters are 786 changed, this option remains -" (a dash followed by a double 787 quote). 788 789 -~ or --tilde 790 Normally lines after end of file are displayed as a single tilde 791 (~). This option causes lines after end of file to be displayed 792 as blank lines. 793 794 -# or --shift 795 Specifies the default number of positions to scroll horizontally 796 in the RIGHTARROW and LEFTARROW commands. If the number speci- 797 fied is zero, it sets the default number of positions to one 798 half of the screen width. 799 800 -- A command line argument of "--" marks the end of option argu- 801 ments. Any arguments following this are interpreted as file- 802 names. This can be useful when viewing a file whose name begins 803 with a "-" or "+". 804 805 + If a command line option begins with [1m+[22m, the remainder of that 806 option is taken to be an initial command to [4mless.[24m For example, 807 +G tells [4mless[24m to start at the end of the file rather than the 808 beginning, and +/xyz tells it to start at the first occurrence 809 of "xyz" in the file. As a special case, +<number> acts like 810 +<number>g; that is, it starts the display at the specified line 811 number (however, see the caveat under the "g" command above). 812 If the option starts with ++, the initial command applies to 813 every file being viewed, not just the first one. The + command 814 described previously may also be used to set (or change) an ini- 815 tial command for every file. 816 817 818[1mLINE EDITING[0m 819 When entering command line at the bottom of the screen (for example, a 820 filename for the :e command, or the pattern for a search command), cer- 821 tain keys can be used to manipulate the command line. Most commands 822 have an alternate form in [ brackets ] which can be used if a key does 823 not exist on a particular keyboard. (The bracketed forms do not work 824 in the MS-DOS version.) Any of these special keys may be entered lit- 825 erally by preceding it with the "literal" character, either ^V or ^A. 826 A backslash itself may also be entered literally by entering two back- 827 slashes. 828 829 LEFTARROW [ ESC-h ] 830 Move the cursor one space to the left. 831 832 RIGHTARROW [ ESC-l ] 833 Move the cursor one space to the right. 834 835 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ] 836 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur- 837 sor one word to the left. 838 839 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ] 840 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur- 841 sor one word to the right. 842 843 HOME [ ESC-0 ] 844 Move the cursor to the beginning of the line. 845 846 END [ ESC-$ ] 847 Move the cursor to the end of the line. 848 849 BACKSPACE 850 Delete the character to the left of the cursor, or cancel the 851 command if the command line is empty. 852 853 DELETE or [ ESC-x ] 854 Delete the character under the cursor. 855 856 ^BACKSPACE [ ESC-BACKSPACE ] 857 (That is, CONTROL and BACKSPACE simultaneously.) Delete the 858 word to the left of the cursor. 859 860 ^DELETE [ ESC-X or ESC-DELETE ] 861 (That is, CONTROL and DELETE simultaneously.) Delete the word 862 under the cursor. 863 864 UPARROW [ ESC-k ] 865 Retrieve the previous command line. 866 867 DOWNARROW [ ESC-j ] 868 Retrieve the next command line. 869 870 TAB Complete the partial filename to the left of the cursor. If it 871 matches more than one filename, the first match is entered into 872 the command line. Repeated TABs will cycle thru the other 873 matching filenames. If the completed filename is a directory, a 874 "/" is appended to the filename. (On MS-DOS systems, a "\" is 875 appended.) The environment variable LESSSEPARATOR can be used 876 to specify a different character to append to a directory name. 877 878 BACKTAB [ ESC-TAB ] 879 Like, TAB, but cycles in the reverse direction thru the matching 880 filenames. 881 882 ^L Complete the partial filename to the left of the cursor. If it 883 matches more than one filename, all matches are entered into the 884 command line (if they fit). 885 886 ^U (Unix and OS/2) or ESC (MS-DOS) 887 Delete the entire command line, or cancel the command if the 888 command line is empty. If you have changed your line-kill char- 889 acter in Unix to something other than ^U, that character is used 890 instead of ^U. 891 892 893[1mKEY BINDINGS[0m 894 You may define your own [4mless[24m commands by using the program [4mlesskey[24m (1) 895 to create a lesskey file. This file specifies a set of command keys 896 and an action associated with each key. You may also use [4mlesskey[24m to 897 change the line-editing keys (see LINE EDITING), and to set environment 898 variables. If the environment variable LESSKEY is set, [4mless[24m uses that 899 as the name of the lesskey file. Otherwise, [4mless[24m looks in a standard 900 place for the lesskey file: On Unix systems, [4mless[24m looks for a lesskey 901 file called "$HOME/.less". On MS-DOS and Windows systems, [4mless[24m looks 902 for a lesskey file called "$HOME/_less", and if it is not found there, 903 then looks for a lesskey file called "_less" in any directory specified 904 in the PATH environment variable. On OS/2 systems, [4mless[24m looks for a 905 lesskey file called "$HOME/less.ini", and if it is not found, then 906 looks for a lesskey file called "less.ini" in any directory specified 907 in the INIT environment variable, and if it not found there, then looks 908 for a lesskey file called "less.ini" in any directory specified in the 909 PATH environment variable. See the [4mlesskey[24m manual page for more 910 details. 911 912 A system-wide lesskey file may also be set up to provide key bindings. 913 If a key is defined in both a local lesskey file and in the system-wide 914 file, key bindings in the local file take precedence over those in the 915 system-wide file. If the environment variable LESSKEY_SYSTEM is set, 916 [4mless[24m uses that as the name of the system-wide lesskey file. Otherwise, 917 [4mless[24m looks in a standard place for the system-wide lesskey file: On 918 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. 919 (However, if [4mless[24m was built with a different sysconf directory than 920 /usr/local/etc, that directory is where the sysless file is found.) On 921 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys- 922 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini. 923 924 925[1mINPUT PREPROCESSOR[0m 926 You may define an "input preprocessor" for [4mless.[24m Before [4mless[24m opens a 927 file, it first gives your input preprocessor a chance to modify the way 928 the contents of the file are displayed. An input preprocessor is sim- 929 ply an executable program (or shell script), which writes the contents 930 of the file to a different file, called the replacement file. The con- 931 tents of the replacement file are then displayed in place of the con- 932 tents of the original file. However, it will appear to the user as if 933 the original file is opened; that is, [4mless[24m will display the original 934 filename as the name of the current file. 935 936 An input preprocessor receives one command line argument, the original 937 filename, as entered by the user. It should create the replacement 938 file, and when finished, print the name of the replacement file to its 939 standard output. If the input preprocessor does not output a replace- 940 ment filename, [4mless[24m uses the original file, as normal. The input pre- 941 processor is not called when viewing standard input. To set up an 942 input preprocessor, set the LESSOPEN environment variable to a command 943 line which will invoke your input preprocessor. This command line 944 should include one occurrence of the string "%s", which will be 945 replaced by the filename when the input preprocessor command is 946 invoked. 947 948 When [4mless[24m closes a file opened in such a way, it will call another pro- 949 gram, called the input postprocessor, which may perform any desired 950 clean-up action (such as deleting the replacement file created by 951 LESSOPEN). This program receives two command line arguments, the orig- 952 inal filename as entered by the user, and the name of the replacement 953 file. To set up an input postprocessor, set the LESSCLOSE environment 954 variable to a command line which will invoke your input postprocessor. 955 It may include two occurrences of the string "%s"; the first is 956 replaced with the original name of the file and the second with the 957 name of the replacement file, which was output by LESSOPEN. 958 959 For example, on many Unix systems, these two scripts will allow you to 960 keep files in compressed format, but still let [4mless[24m view them directly: 961 962 lessopen.sh: 963 #! /bin/sh 964 case "$1" in 965 *.Z) uncompress - 966 if [ -s /tmp/less.$$ ]; then 967 echo /tmp/less.$$ 968 else 969 rm -f /tmp/less.$$ 970 fi 971 ;; 972 esac 973 974 lessclose.sh: 975 #! /bin/sh 976 rm $2 977 978 To use these scripts, put them both where they can be executed and set 979 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More 980 complex LESSOPEN and LESSCLOSE scripts may be written to accept other 981 types of compressed files, and so on. 982 983 It is also possible to set up an input preprocessor to pipe the file 984 data directly to [4mless,[24m rather than putting the data into a replacement 985 file. This avoids the need to decompress the entire file before start- 986 ing to view it. An input preprocessor that works this way is called an 987 input pipe. An input pipe, instead of writing the name of a replace- 988 ment file on its standard output, writes the entire contents of the 989 replacement file on its standard output. If the input pipe does not 990 write any characters on its standard output, then there is no replace- 991 ment file and [4mless[24m uses the original file, as normal. To use an input 992 pipe, make the first character in the LESSOPEN environment variable a 993 vertical bar (|) to signify that the input preprocessor is an input 994 pipe. 995 996 For example, on many Unix systems, this script will work like the pre- 997 vious example scripts: 998 999 lesspipe.sh: 1000 #! /bin/sh 1001 case "$1" in 1002 *.Z) uncompress -c $1 2>/dev/null 1003 ;; 1004 esac 1005 1006 To use this script, put it where it can be executed and set 1007 LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a LESSCLOSE 1008 postprocessor can be used, but it is usually not necessary since there 1009 is no replacement file to clean up. In this case, the replacement file 1010 name passed to the LESSCLOSE postprocessor is "-". 1011 1012 1013[1mNATIONAL CHARACTER SETS[0m 1014 There are three types of characters in the input file: 1015 1016 normal characters 1017 can be displayed directly to the screen. 1018 1019 control characters 1020 should not be displayed directly, but are expected to be found 1021 in ordinary text files (such as backspace and tab). 1022 1023 binary characters 1024 should not be displayed directly and are not expected to be 1025 found in text files. 1026 1027 A "character set" is simply a description of which characters are to be 1028 considered normal, control, and binary. The LESSCHARSET environment 1029 variable may be used to select a character set. Possible values for 1030 LESSCHARSET are: 1031 1032 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars 1033 with values between 32 and 126 are normal, and all others are 1034 binary. 1035 1036 iso8859 1037 Selects an ISO 8859 character set. This is the same as ASCII, 1038 except characters between 160 and 255 are treated as normal 1039 characters. 1040 1041 latin1 Same as iso8859. 1042 1043 latin9 Same as iso8859. 1044 1045 dos Selects a character set appropriate for MS-DOS. 1046 1047 ebcdic Selects an EBCDIC character set. 1048 1049 IBM-1047 1050 Selects an EBCDIC character set used by OS/390 Unix Services. 1051 This is the EBCDIC analogue of latin1. You get similar results 1052 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your 1053 environment. 1054 1055 koi8-r Selects a Russian character set. 1056 1057 next Selects a character set appropriate for NeXT computers. 1058 1059 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. 1060 UTF-8 is special in that it supports multi-byte characters in 1061 the input file. It is the only character set that supports 1062 multi-byte characters. 1063 1064 windows 1065 Selects a character set appropriate for Microsoft Windows (cp 1066 1251). 1067 1068 In special cases, it may be desired to tailor [4mless[24m to use a character 1069 set other than the ones definable by LESSCHARSET. In this case, the 1070 environment variable LESSCHARDEF can be used to define a character set. 1071 It should be set to a string where each character in the string repre- 1072 sents one character in the character set. The character "." is used 1073 for a normal character, "c" for control, and "b" for binary. A decimal 1074 number may be used for repetition. For example, "bccc4b." would mean 1075 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are 1076 binary, and 8 is normal. All characters after the last are taken to be 1077 the same as the last, so characters 9 through 255 would be normal. 1078 (This is an example, and does not necessarily represent any real char- 1079 acter set.) 1080 1081 This table shows the value of LESSCHARDEF which is equivalent to each 1082 of the possible values for LESSCHARSET: 1083 1084 ascii 8bcccbcc18b95.b 1085 dos 8bcccbcc12bc5b95.b. 1086 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b 1087 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b. 1088 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc 1089 191.b 1090 iso8859 8bcccbcc18b95.33b. 1091 koi8-r 8bcccbcc18b95.b128. 1092 latin1 8bcccbcc18b95.33b. 1093 next 8bcccbcc18b95.bb125.bb 1094 1095 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings 1096 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_TYPE or 1097 LANG environment variables, then the default character set is utf-8. 1098 1099 If that string is not found, but your system supports the [4msetlocale[0m 1100 interface, [4mless[24m will use setlocale to determine the character set. 1101 setlocale is controlled by setting the LANG or LC_CTYPE environment 1102 variables. 1103 1104 Finally, if the [4msetlocale[24m interface is also not available, the default 1105 character set is latin1. 1106 1107 Control and binary characters are displayed in standout (reverse 1108 video). Each such character is displayed in caret notation if possible 1109 (e.g. ^A for control-A). Caret notation is used only if inverting the 1110 0100 bit results in a normal printable character. Otherwise, the char- 1111 acter is displayed as a hex number in angle brackets. This format can 1112 be changed by setting the LESSBINFMT environment variable. LESSBINFMT 1113 may begin with a "*" and one character to select the display attribute: 1114 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout, 1115 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal 1116 attribute is assumed. The remainder of LESSBINFMT is a string which 1117 may include one printf-style escape sequence (a % followed by x, X, o, 1118 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters 1119 are displayed in underlined hexadecimal surrounded by brackets. The 1120 default if no LESSBINFMT is specified is "*s<%X>". The default if no 1121 LESSBINFMT is specified is "*s<%02X>". Warning: the result of expand- 1122 ing the character via LESSBINFMT must be less than 31 characters. 1123 1124 When the character set is utf-8, the LESSUTFBINFMT environment variable 1125 acts similarly to LESSBINFMT but it applies to Unicode code points that 1126 were successfully decoded but are unsuitable for display (e.g., unas- 1127 signed code points). Its default value is "<U+%04lX>". Note that 1128 LESSUTFBINFMT and LESSBINFMT share their display attribute setting 1129 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after 1130 LESSBINFMT so its setting, if any, will have priority. Problematic 1131 octets in a UTF-8 file (octets of a truncated sequence, octets of a 1132 complete but non-shortest form sequence, illegal octets, and stray 1133 trailing octets) are displayed individually using LESSBINFMT so as to 1134 facilitate diagnostic of how the UTF-8 file is ill-formed. 1135 1136 1137[1mPROMPTS[0m 1138 The -P option allows you to tailor the prompt to your preference. The 1139 string given to the -P option replaces the specified prompt string. 1140 Certain characters in the string are interpreted specially. The prompt 1141 mechanism is rather complicated to provide flexibility, but the ordi- 1142 nary user need not understand the details of constructing personalized 1143 prompt strings. 1144 1145 A percent sign followed by a single character is expanded according to 1146 what the following character is: 1147 1148 %b[4mX[24m Replaced by the byte offset into the current input file. The b 1149 is followed by a single character (shown as [4mX[24m above) which spec- 1150 ifies the line whose byte offset is to be used. If the charac- 1151 ter is a "t", the byte offset of the top line in the display is 1152 used, an "m" means use the middle line, a "b" means use the bot- 1153 tom line, a "B" means use the line just after the bottom line, 1154 and a "j" means use the "target" line, as specified by the -j 1155 option. 1156 1157 %B Replaced by the size of the current input file. 1158 1159 %c Replaced by the column number of the text appearing in the first 1160 column of the screen. 1161 1162 %d[4mX[24m Replaced by the page number of a line in the input file. The 1163 line to be used is determined by the [4mX[24m, as with the %b option. 1164 1165 %D Replaced by the number of pages in the input file, or equiva- 1166 lently, the page number of the last line in the input file. 1167 1168 %E Replaced by the name of the editor (from the VISUAL environment 1169 variable, or the EDITOR environment variable if VISUAL is not 1170 defined). See the discussion of the LESSEDIT feature below. 1171 1172 %f Replaced by the name of the current input file. 1173 1174 %i Replaced by the index of the current file in the list of input 1175 files. 1176 1177 %l[4mX[24m Replaced by the line number of a line in the input file. The 1178 line to be used is determined by the [4mX[24m, as with the %b option. 1179 1180 %L Replaced by the line number of the last line in the input file. 1181 1182 %m Replaced by the total number of input files. 1183 1184 %p[4mX[24m Replaced by the percent into the current input file, based on 1185 byte offsets. The line used is determined by the [4mX[24m as with the 1186 %b option. 1187 1188 %P[4mX[24m Replaced by the percent into the current input file, based on 1189 line numbers. The line used is determined by the [4mX[24m as with the 1190 %b option. 1191 1192 %s Same as %B. 1193 1194 %t Causes any trailing spaces to be removed. Usually used at the 1195 end of the string, but may appear anywhere. 1196 1197 %x Replaced by the name of the next input file in the list. 1198 1199 If any item is unknown (for example, the file size if input is a pipe), 1200 a question mark is printed instead. 1201 1202 The format of the prompt string can be changed depending on certain 1203 conditions. A question mark followed by a single character acts like 1204 an "IF": depending on the following character, a condition is evalu- 1205 ated. If the condition is true, any characters following the question 1206 mark and condition character, up to a period, are included in the 1207 prompt. If the condition is false, such characters are not included. 1208 A colon appearing between the question mark and the period can be used 1209 to establish an "ELSE": any characters between the colon and the period 1210 are included in the string if and only if the IF condition is false. 1211 Condition characters (which follow a question mark) may be: 1212 1213 ?a True if any characters have been included in the prompt so far. 1214 1215 ?b[4mX[24m True if the byte offset of the specified line is known. 1216 1217 ?B True if the size of current input file is known. 1218 1219 ?c True if the text is horizontally shifted (%c is not zero). 1220 1221 ?d[4mX[24m True if the page number of the specified line is known. 1222 1223 ?e True if at end-of-file. 1224 1225 ?f True if there is an input filename (that is, if input is not a 1226 pipe). 1227 1228 ?l[4mX[24m True if the line number of the specified line is known. 1229 1230 ?L True if the line number of the last line in the file is known. 1231 1232 ?m True if there is more than one input file. 1233 1234 ?n True if this is the first prompt in a new input file. 1235 1236 ?p[4mX[24m True if the percent into the current input file, based on byte 1237 offsets, of the specified line is known. 1238 1239 ?P[4mX[24m True if the percent into the current input file, based on line 1240 numbers, of the specified line is known. 1241 1242 ?s Same as "?B". 1243 1244 ?x True if there is a next input file (that is, if the current 1245 input file is not the last one). 1246 1247 Any characters other than the special ones (question mark, colon, 1248 period, percent, and backslash) become literally part of the prompt. 1249 Any of the special characters may be included in the prompt literally 1250 by preceding it with a backslash. 1251 1252 Some examples: 1253 1254 ?f%f:Standard input. 1255 1256 This prompt prints the filename, if known; otherwise the string "Stan- 1257 dard input". 1258 1259 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-... 1260 1261 This prompt would print the filename, if known. The filename is fol- 1262 lowed by the line number, if known, otherwise the percent if known, 1263 otherwise the byte offset if known. Otherwise, a dash is printed. 1264 Notice how each question mark has a matching period, and how the % 1265 after the %pt is included literally by escaping it with a backslash. 1266 1267 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t 1268 1269 This prints the filename if this is the first prompt in a file, fol- 1270 lowed by the "file N of N" message if there is more than one input 1271 file. Then, if we are at end-of-file, the string "(END)" is printed 1272 followed by the name of the next file, if there is one. Finally, any 1273 trailing spaces are truncated. This is the default prompt. For refer- 1274 ence, here are the defaults for the other two prompts (-m and -M 1275 respectively). Each is broken into two lines here for readability 1276 only. 1277 1278 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.: 1279 ?pB%pB\%:byte %bB?s/%s...%t 1280 1281 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. : 1282 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t 1283 1284 And here is the default message produced by the = command: 1285 1286 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. . 1287 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t 1288 1289 The prompt expansion features are also used for another purpose: if an 1290 environment variable LESSEDIT is defined, it is used as the command to 1291 be executed when the v command is invoked. The LESSEDIT string is 1292 expanded in the same way as the prompt strings. The default value for 1293 LESSEDIT is: 1294 1295 %E ?lm+%lm. %f 1296 1297 Note that this expands to the editor name, followed by a + and the line 1298 number, followed by the file name. If your editor does not accept the 1299 "+linenumber" syntax, or has other differences in invocation syntax, 1300 the LESSEDIT variable can be changed to modify this default. 1301 1302 1303[1mSECURITY[0m 1304 When the environment variable LESSSECURE is set to 1, [4mless[24m runs in a 1305 "secure" mode. This means these features are disabled: 1306 1307 ! the shell command 1308 1309 | the pipe command 1310 1311 :e the examine command. 1312 1313 v the editing command 1314 1315 s -o log files 1316 1317 -k use of lesskey files 1318 1319 -t use of tags files 1320 1321 metacharacters in filenames, such as * 1322 1323 filename completion (TAB, ^L) 1324 1325 Less can also be compiled to be permanently in "secure" mode. 1326 1327 1328[1mCOMPATIBILITY WITH MORE[0m 1329 If the environment variable LESS_IS_MORE is set to 1, or if the program 1330 is invoked via a file link named "more", [4mless[24m behaves (mostly) in con- 1331 formance with the POSIX "more" command specification. In this mode, 1332 less behaves differently in these ways: 1333 1334 The -e option works differently. If the -e option is not set, [4mless[0m 1335 behaves as if the -E option were set. If the -e option is set, [4mless[0m 1336 behaves as if the -e and -F options were set. 1337 1338 The -m option works differently. If the -m option is not set, the 1339 medium prompt is used, and it is prefixed with the string "--More--". 1340 If the -m option is set, the short prompt is used. 1341 1342 The -n option acts like the -z option. The normal behavior of the -n 1343 option is unavailable in this mode. 1344 1345 The parameter to the -p option is taken to be a [4mless[24m command rather 1346 than a search pattern. 1347 1348 The LESS environment variable is ignored, and the MORE environment 1349 variable is used in its place. 1350 1351 1352[1mENVIRONMENT VARIABLES[0m 1353 Environment variables may be specified either in the system environment 1354 as usual, or in a [4mlesskey[24m (1) file. If environment variables are 1355 defined in more than one place, variables defined in a local lesskey 1356 file take precedence over variables defined in the system environment, 1357 which take precedence over variables defined in the system-wide lesskey 1358 file. 1359 1360 COLUMNS 1361 Sets the number of columns on the screen. Takes precedence over 1362 the number of columns specified by the TERM variable. (But if 1363 you have a windowing system which supports TIOCGWINSZ or 1364 WIOCGETD, the window system's idea of the screen size takes 1365 precedence over the LINES and COLUMNS environment variables.) 1366 1367 EDITOR The name of the editor (used for the v command). 1368 1369 HOME Name of the user's home directory (used to find a lesskey file 1370 on Unix and OS/2 systems). 1371 1372 HOMEDRIVE, HOMEPATH 1373 Concatenation of the HOMEDRIVE and HOMEPATH environment vari- 1374 ables is the name of the user's home directory if the HOME vari- 1375 able is not set (only in the Windows version). 1376 1377 INIT Name of the user's init directory (used to find a lesskey file 1378 on OS/2 systems). 1379 1380 LANG Language for determining the character set. 1381 1382 LC_CTYPE 1383 Language for determining the character set. 1384 1385 LESS Options which are passed to [4mless[24m automatically. 1386 1387 LESSANSIENDCHARS 1388 Characters which may end an ANSI color escape sequence (default 1389 "m"). 1390 1391 LESSANSIMIDCHARS 1392 Characters which may appear between the ESC character and the 1393 end character in an ANSI color escape sequence (default 1394 "0123456789;[?!"'#%()*+ ". 1395 1396 LESSBINFMT 1397 Format for displaying non-printable, non-control characters. 1398 1399 LESSCHARDEF 1400 Defines a character set. 1401 1402 LESSCHARSET 1403 Selects a predefined character set. 1404 1405 LESSCLOSE 1406 Command line to invoke the (optional) input-postprocessor. 1407 1408 LESSECHO 1409 Name of the lessecho program (default "lessecho"). The lessecho 1410 program is needed to expand metacharacters, such as * and ?, in 1411 filenames on Unix systems. 1412 1413 LESSEDIT 1414 Editor prototype string (used for the v command). See discus- 1415 sion under PROMPTS. 1416 1417 LESSGLOBALTAGS 1418 Name of the command used by the -t option to find global tags. 1419 Normally should be set to "global" if your system has the [4mglobal[0m 1420 (1) command. If not set, global tags are not used. 1421 1422 LESSHISTFILE 1423 Name of the history file used to remember search commands and 1424 shell commands between invocations of [4mless.[24m If set to "-" or 1425 "/dev/null", a history file is not used. The default is 1426 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and 1427 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini" 1428 on OS/2 systems. 1429 1430 LESSHISTSIZE 1431 The maximum number of commands to save in the history file. The 1432 default is 100. 1433 1434 LESSKEY 1435 Name of the default lesskey(1) file. 1436 1437 LESSKEY_SYSTEM 1438 Name of the default system-wide lesskey(1) file. 1439 1440 LESSMETACHARS 1441 List of characters which are considered "metacharacters" by the 1442 shell. 1443 1444 LESSMETAESCAPE 1445 Prefix which less will add before each metacharacter in a com- 1446 mand sent to the shell. If LESSMETAESCAPE is an empty string, 1447 commands containing metacharacters will not be passed to the 1448 shell. 1449 1450 LESSOPEN 1451 Command line to invoke the (optional) input-preprocessor. 1452 1453 LESSSECURE 1454 Runs less in "secure" mode. See discussion under SECURITY. 1455 1456 LESSSEPARATOR 1457 String to be appended to a directory name in filename comple- 1458 tion. 1459 1460 LESSUTFBINFMT 1461 Format for displaying non-printable Unicode code points. 1462 1463 LESS_IS_MORE 1464 Emulate the [4mmore[24m (1) command. 1465 1466 LINES Sets the number of lines on the screen. Takes precedence over 1467 the number of lines specified by the TERM variable. (But if you 1468 have a windowing system which supports TIOCGWINSZ or WIOCGETD, 1469 the window system's idea of the screen size takes precedence 1470 over the LINES and COLUMNS environment variables.) 1471 1472 PATH User's search path (used to find a lesskey file on MS-DOS and 1473 OS/2 systems). 1474 1475 SHELL The shell used to execute the ! command, as well as to expand 1476 filenames. 1477 1478 TERM The type of terminal on which [4mless[24m is being run. 1479 1480 VISUAL The name of the editor (used for the v command). 1481 1482 1483[1mSEE ALSO[0m 1484 lesskey(1) 1485 1486 1487[1mWARNINGS[0m 1488 The = command and prompts (unless changed by -P) report the line num- 1489 bers of the lines at the top and bottom of the screen, but the byte and 1490 percent of the line after the one at the bottom of the screen. 1491 1492 On certain older terminals (the so-called "magic cookie" terminals), 1493 search highlighting will cause an erroneous display. On such termi- 1494 nals, search highlighting is disabled by default to avoid possible 1495 problems. 1496 1497 When searching in a binary file, text which follows a null byte may not 1498 be found. This problem does not occur when searching with regular 1499 expressions turned off via ^R, and also does not occur when [4mless[24m is 1500 compiled to use the PCRE regular expression library. 1501 1502 In certain cases, when search highlighting is enabled and a search pat- 1503 tern begins with a ^, more text than the matching string may be high- 1504 lighted. (This problem does not occur when less is compiled to use the 1505 POSIX regular expression package.) 1506 1507 On some systems, [4msetlocale[24m claims that ASCII characters 0 thru 31 are 1508 control characters rather than binary characters. This causes [4mless[24m to 1509 treat some binary files as ordinary, non-binary files. To workaround 1510 this problem, set the environment variable LESSCHARSET to "ascii" (or 1511 whatever character set is appropriate). 1512 1513 This manual is too long. 1514 1515 See http://www.greenwoodsoftware.com/less for the latest list of known 1516 bugs in less. 1517 1518 1519[1mCOPYRIGHT[0m 1520 Copyright (C) 1984-2007 Mark Nudelman 1521 1522 less is part of the GNU project and is free software. You can redis- 1523 tribute it and/or modify it under the terms of either (1) the GNU Gen- 1524 eral Public License as published by the Free Software Foundation; or 1525 (2) the Less License. See the file README in the less distribution for 1526 more details regarding redistribution. You should have received a copy 1527 of the GNU General Public License along with the source for less; see 1528 the file COPYING. If not, write to the Free Software Foundation, 59 1529 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also 1530 have received a copy of the Less License; see the file LICENSE. 1531 1532 less is distributed in the hope that it will be useful, but WITHOUT ANY 1533 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT- 1534 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 1535 more details. 1536 1537 1538[1mAUTHOR[0m 1539 Mark Nudelman <markn@greenwoodsoftware.com> 1540 Send bug reports or comments to the above address or to 1541 bug-less@gnu.org. 1542 For more information, see the less homepage at 1543 http://www.greenwoodsoftware.com/less. 1544 1545 1546 1547 Version 406: 19 Jun 2007 LESS(1) 1548