less.man revision 173682
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 -y[4mn[24m or --max-forw-scroll=[4mn[0m 754 Specifies a maximum number of lines to scroll forward. If it is 755 necessary to scroll forward more than [4mn[24m lines, the screen is 756 repainted instead. The -c or -C option may be used to repaint 757 from the top of the screen if desired. By default, any forward 758 movement causes scrolling. 759 760 -[z][4mn[24m or --window=[4mn[0m 761 Changes the default scrolling window size to [4mn[24m lines. The 762 default is one screenful. The z and w commands can also be used 763 to change the window size. The "z" may be omitted for compati- 764 bility with some versions of [4mmore.[24m If the number [4mn[24m is negative, 765 it indicates [4mn[24m lines less than the current screen size. For 766 example, if the screen is 24 lines, [4m-z-4[24m sets the scrolling win- 767 dow to 20 lines. If the screen is resized to 40 lines, the 768 scrolling window automatically changes to 36 lines. 769 770 -[4m"cc[24m or --quotes=[4mcc[0m 771 Changes the filename quoting character. This may be necessary 772 if you are trying to name a file which contains both spaces and 773 quote characters. Followed by a single character, this changes 774 the quote character to that character. Filenames containing a 775 space should then be surrounded by that character rather than by 776 double quotes. Followed by two characters, changes the open 777 quote to the first character, and the close quote to the second 778 character. Filenames containing a space should then be preceded 779 by the open quote character and followed by the close quote 780 character. Note that even after the quote characters are 781 changed, this option remains -" (a dash followed by a double 782 quote). 783 784 -~ or --tilde 785 Normally lines after end of file are displayed as a single tilde 786 (~). This option causes lines after end of file to be displayed 787 as blank lines. 788 789 -# or --shift 790 Specifies the default number of positions to scroll horizontally 791 in the RIGHTARROW and LEFTARROW commands. If the number speci- 792 fied is zero, it sets the default number of positions to one 793 half of the screen width. 794 795 --no-keypad 796 Disables sending the keypad initialization and deinitialization 797 strings to the terminal. This is sometimes useful if the keypad 798 strings make the numeric keypad behave in an undesirable manner. 799 800 --follow-name 801 Normally, if the input file is renamed while an F command is 802 executing, [4mless[24m will continue to display the contents of the 803 original file despite its name change. If --follow-name is 804 specified, during an F command [4mless[24m will periodically attempt to 805 reopen the file by name. If the reopen succeeds and the file is 806 a different file from the original (which means that a new file 807 has been created with the same name as the original (now 808 renamed) file), [4mless[24m will display the contents of that new file. 809 810 -- A command line argument of "--" marks the end of option argu- 811 ments. Any arguments following this are interpreted as file- 812 names. This can be useful when viewing a file whose name begins 813 with a "-" or "+". 814 815 + If a command line option begins with [1m+[22m, the remainder of that 816 option is taken to be an initial command to [4mless.[24m For example, 817 +G tells [4mless[24m to start at the end of the file rather than the 818 beginning, and +/xyz tells it to start at the first occurrence 819 of "xyz" in the file. As a special case, +<number> acts like 820 +<number>g; that is, it starts the display at the specified line 821 number (however, see the caveat under the "g" command above). 822 If the option starts with ++, the initial command applies to 823 every file being viewed, not just the first one. The + command 824 described previously may also be used to set (or change) an ini- 825 tial command for every file. 826 827 828[1mLINE EDITING[0m 829 When entering command line at the bottom of the screen (for example, a 830 filename for the :e command, or the pattern for a search command), cer- 831 tain keys can be used to manipulate the command line. Most commands 832 have an alternate form in [ brackets ] which can be used if a key does 833 not exist on a particular keyboard. (The bracketed forms do not work 834 in the MS-DOS version.) Any of these special keys may be entered lit- 835 erally by preceding it with the "literal" character, either ^V or ^A. 836 A backslash itself may also be entered literally by entering two back- 837 slashes. 838 839 LEFTARROW [ ESC-h ] 840 Move the cursor one space to the left. 841 842 RIGHTARROW [ ESC-l ] 843 Move the cursor one space to the right. 844 845 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ] 846 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur- 847 sor one word to the left. 848 849 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ] 850 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur- 851 sor one word to the right. 852 853 HOME [ ESC-0 ] 854 Move the cursor to the beginning of the line. 855 856 END [ ESC-$ ] 857 Move the cursor to the end of the line. 858 859 BACKSPACE 860 Delete the character to the left of the cursor, or cancel the 861 command if the command line is empty. 862 863 DELETE or [ ESC-x ] 864 Delete the character under the cursor. 865 866 ^BACKSPACE [ ESC-BACKSPACE ] 867 (That is, CONTROL and BACKSPACE simultaneously.) Delete the 868 word to the left of the cursor. 869 870 ^DELETE [ ESC-X or ESC-DELETE ] 871 (That is, CONTROL and DELETE simultaneously.) Delete the word 872 under the cursor. 873 874 UPARROW [ ESC-k ] 875 Retrieve the previous command line. 876 877 DOWNARROW [ ESC-j ] 878 Retrieve the next command line. 879 880 TAB Complete the partial filename to the left of the cursor. If it 881 matches more than one filename, the first match is entered into 882 the command line. Repeated TABs will cycle thru the other 883 matching filenames. If the completed filename is a directory, a 884 "/" is appended to the filename. (On MS-DOS systems, a "\" is 885 appended.) The environment variable LESSSEPARATOR can be used 886 to specify a different character to append to a directory name. 887 888 BACKTAB [ ESC-TAB ] 889 Like, TAB, but cycles in the reverse direction thru the matching 890 filenames. 891 892 ^L Complete the partial filename to the left of the cursor. If it 893 matches more than one filename, all matches are entered into the 894 command line (if they fit). 895 896 ^U (Unix and OS/2) or ESC (MS-DOS) 897 Delete the entire command line, or cancel the command if the 898 command line is empty. If you have changed your line-kill char- 899 acter in Unix to something other than ^U, that character is used 900 instead of ^U. 901 902 903[1mKEY BINDINGS[0m 904 You may define your own [4mless[24m commands by using the program [4mlesskey[24m (1) 905 to create a lesskey file. This file specifies a set of command keys 906 and an action associated with each key. You may also use [4mlesskey[24m to 907 change the line-editing keys (see LINE EDITING), and to set environment 908 variables. If the environment variable LESSKEY is set, [4mless[24m uses that 909 as the name of the lesskey file. Otherwise, [4mless[24m looks in a standard 910 place for the lesskey file: On Unix systems, [4mless[24m looks for a lesskey 911 file called "$HOME/.less". On MS-DOS and Windows systems, [4mless[24m looks 912 for a lesskey file called "$HOME/_less", and if it is not found there, 913 then looks for a lesskey file called "_less" in any directory specified 914 in the PATH environment variable. On OS/2 systems, [4mless[24m looks for a 915 lesskey file called "$HOME/less.ini", and if it is not found, then 916 looks for a lesskey file called "less.ini" in any directory specified 917 in the INIT environment variable, and if it not found there, then looks 918 for a lesskey file called "less.ini" in any directory specified in the 919 PATH environment variable. See the [4mlesskey[24m manual page for more 920 details. 921 922 A system-wide lesskey file may also be set up to provide key bindings. 923 If a key is defined in both a local lesskey file and in the system-wide 924 file, key bindings in the local file take precedence over those in the 925 system-wide file. If the environment variable LESSKEY_SYSTEM is set, 926 [4mless[24m uses that as the name of the system-wide lesskey file. Otherwise, 927 [4mless[24m looks in a standard place for the system-wide lesskey file: On 928 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. 929 (However, if [4mless[24m was built with a different sysconf directory than 930 /usr/local/etc, that directory is where the sysless file is found.) On 931 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys- 932 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini. 933 934 935[1mINPUT PREPROCESSOR[0m 936 You may define an "input preprocessor" for [4mless.[24m Before [4mless[24m opens a 937 file, it first gives your input preprocessor a chance to modify the way 938 the contents of the file are displayed. An input preprocessor is sim- 939 ply an executable program (or shell script), which writes the contents 940 of the file to a different file, called the replacement file. The con- 941 tents of the replacement file are then displayed in place of the con- 942 tents of the original file. However, it will appear to the user as if 943 the original file is opened; that is, [4mless[24m will display the original 944 filename as the name of the current file. 945 946 An input preprocessor receives one command line argument, the original 947 filename, as entered by the user. It should create the replacement 948 file, and when finished, print the name of the replacement file to its 949 standard output. If the input preprocessor does not output a replace- 950 ment filename, [4mless[24m uses the original file, as normal. The input pre- 951 processor is not called when viewing standard input. To set up an 952 input preprocessor, set the LESSOPEN environment variable to a command 953 line which will invoke your input preprocessor. This command line 954 should include one occurrence of the string "%s", which will be 955 replaced by the filename when the input preprocessor command is 956 invoked. 957 958 When [4mless[24m closes a file opened in such a way, it will call another pro- 959 gram, called the input postprocessor, which may perform any desired 960 clean-up action (such as deleting the replacement file created by 961 LESSOPEN). This program receives two command line arguments, the orig- 962 inal filename as entered by the user, and the name of the replacement 963 file. To set up an input postprocessor, set the LESSCLOSE environment 964 variable to a command line which will invoke your input postprocessor. 965 It may include two occurrences of the string "%s"; the first is 966 replaced with the original name of the file and the second with the 967 name of the replacement file, which was output by LESSOPEN. 968 969 For example, on many Unix systems, these two scripts will allow you to 970 keep files in compressed format, but still let [4mless[24m view them directly: 971 972 lessopen.sh: 973 #! /bin/sh 974 case "$1" in 975 *.Z) uncompress - 976 if [ -s /tmp/less.$$ ]; then 977 echo /tmp/less.$$ 978 else 979 rm -f /tmp/less.$$ 980 fi 981 ;; 982 esac 983 984 lessclose.sh: 985 #! /bin/sh 986 rm $2 987 988 To use these scripts, put them both where they can be executed and set 989 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More 990 complex LESSOPEN and LESSCLOSE scripts may be written to accept other 991 types of compressed files, and so on. 992 993 It is also possible to set up an input preprocessor to pipe the file 994 data directly to [4mless,[24m rather than putting the data into a replacement 995 file. This avoids the need to decompress the entire file before start- 996 ing to view it. An input preprocessor that works this way is called an 997 input pipe. An input pipe, instead of writing the name of a replace- 998 ment file on its standard output, writes the entire contents of the 999 replacement file on its standard output. If the input pipe does not 1000 write any characters on its standard output, then there is no replace- 1001 ment file and [4mless[24m uses the original file, as normal. To use an input 1002 pipe, make the first character in the LESSOPEN environment variable a 1003 vertical bar (|) to signify that the input preprocessor is an input 1004 pipe. 1005 1006 For example, on many Unix systems, this script will work like the pre- 1007 vious example scripts: 1008 1009 lesspipe.sh: 1010 #! /bin/sh 1011 case "$1" in 1012 *.Z) uncompress -c $1 2>/dev/null 1013 ;; 1014 esac 1015 1016 To use this script, put it where it can be executed and set 1017 LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a LESSCLOSE 1018 postprocessor can be used, but it is usually not necessary since there 1019 is no replacement file to clean up. In this case, the replacement file 1020 name passed to the LESSCLOSE postprocessor is "-". 1021 1022 1023[1mNATIONAL CHARACTER SETS[0m 1024 There are three types of characters in the input file: 1025 1026 normal characters 1027 can be displayed directly to the screen. 1028 1029 control characters 1030 should not be displayed directly, but are expected to be found 1031 in ordinary text files (such as backspace and tab). 1032 1033 binary characters 1034 should not be displayed directly and are not expected to be 1035 found in text files. 1036 1037 A "character set" is simply a description of which characters are to be 1038 considered normal, control, and binary. The LESSCHARSET environment 1039 variable may be used to select a character set. Possible values for 1040 LESSCHARSET are: 1041 1042 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars 1043 with values between 32 and 126 are normal, and all others are 1044 binary. 1045 1046 iso8859 1047 Selects an ISO 8859 character set. This is the same as ASCII, 1048 except characters between 160 and 255 are treated as normal 1049 characters. 1050 1051 latin1 Same as iso8859. 1052 1053 latin9 Same as iso8859. 1054 1055 dos Selects a character set appropriate for MS-DOS. 1056 1057 ebcdic Selects an EBCDIC character set. 1058 1059 IBM-1047 1060 Selects an EBCDIC character set used by OS/390 Unix Services. 1061 This is the EBCDIC analogue of latin1. You get similar results 1062 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your 1063 environment. 1064 1065 koi8-r Selects a Russian character set. 1066 1067 next Selects a character set appropriate for NeXT computers. 1068 1069 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. 1070 UTF-8 is special in that it supports multi-byte characters in 1071 the input file. It is the only character set that supports 1072 multi-byte characters. 1073 1074 windows 1075 Selects a character set appropriate for Microsoft Windows (cp 1076 1251). 1077 1078 In special cases, it may be desired to tailor [4mless[24m to use a character 1079 set other than the ones definable by LESSCHARSET. In this case, the 1080 environment variable LESSCHARDEF can be used to define a character set. 1081 It should be set to a string where each character in the string repre- 1082 sents one character in the character set. The character "." is used 1083 for a normal character, "c" for control, and "b" for binary. A decimal 1084 number may be used for repetition. For example, "bccc4b." would mean 1085 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are 1086 binary, and 8 is normal. All characters after the last are taken to be 1087 the same as the last, so characters 9 through 255 would be normal. 1088 (This is an example, and does not necessarily represent any real char- 1089 acter set.) 1090 1091 This table shows the value of LESSCHARDEF which is equivalent to each 1092 of the possible values for LESSCHARSET: 1093 1094 ascii 8bcccbcc18b95.b 1095 dos 8bcccbcc12bc5b95.b. 1096 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b 1097 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b. 1098 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc 1099 191.b 1100 iso8859 8bcccbcc18b95.33b. 1101 koi8-r 8bcccbcc18b95.b128. 1102 latin1 8bcccbcc18b95.33b. 1103 next 8bcccbcc18b95.bb125.bb 1104 1105 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings 1106 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_TYPE or 1107 LANG environment variables, then the default character set is utf-8. 1108 1109 If that string is not found, but your system supports the [4msetlocale[0m 1110 interface, [4mless[24m will use setlocale to determine the character set. 1111 setlocale is controlled by setting the LANG or LC_CTYPE environment 1112 variables. 1113 1114 Finally, if the [4msetlocale[24m interface is also not available, the default 1115 character set is latin1. 1116 1117 Control and binary characters are displayed in standout (reverse 1118 video). Each such character is displayed in caret notation if possible 1119 (e.g. ^A for control-A). Caret notation is used only if inverting the 1120 0100 bit results in a normal printable character. Otherwise, the char- 1121 acter is displayed as a hex number in angle brackets. This format can 1122 be changed by setting the LESSBINFMT environment variable. LESSBINFMT 1123 may begin with a "*" and one character to select the display attribute: 1124 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout, 1125 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal 1126 attribute is assumed. The remainder of LESSBINFMT is a string which 1127 may include one printf-style escape sequence (a % followed by x, X, o, 1128 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters 1129 are displayed in underlined hexadecimal surrounded by brackets. The 1130 default if no LESSBINFMT is specified is "*s<%X>". The default if no 1131 LESSBINFMT is specified is "*s<%02X>". Warning: the result of expand- 1132 ing the character via LESSBINFMT must be less than 31 characters. 1133 1134 When the character set is utf-8, the LESSUTFBINFMT environment variable 1135 acts similarly to LESSBINFMT but it applies to Unicode code points that 1136 were successfully decoded but are unsuitable for display (e.g., unas- 1137 signed code points). Its default value is "<U+%04lX>". Note that 1138 LESSUTFBINFMT and LESSBINFMT share their display attribute setting 1139 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after 1140 LESSBINFMT so its setting, if any, will have priority. Problematic 1141 octets in a UTF-8 file (octets of a truncated sequence, octets of a 1142 complete but non-shortest form sequence, illegal octets, and stray 1143 trailing octets) are displayed individually using LESSBINFMT so as to 1144 facilitate diagnostic of how the UTF-8 file is ill-formed. 1145 1146 1147[1mPROMPTS[0m 1148 The -P option allows you to tailor the prompt to your preference. The 1149 string given to the -P option replaces the specified prompt string. 1150 Certain characters in the string are interpreted specially. The prompt 1151 mechanism is rather complicated to provide flexibility, but the ordi- 1152 nary user need not understand the details of constructing personalized 1153 prompt strings. 1154 1155 A percent sign followed by a single character is expanded according to 1156 what the following character is: 1157 1158 %b[4mX[24m Replaced by the byte offset into the current input file. The b 1159 is followed by a single character (shown as [4mX[24m above) which spec- 1160 ifies the line whose byte offset is to be used. If the charac- 1161 ter is a "t", the byte offset of the top line in the display is 1162 used, an "m" means use the middle line, a "b" means use the 1163 bottom line, a "B" means use the line just after the bottom 1164 line, and a "j" means use the "target" line, as specified by the 1165 -j option. 1166 1167 %B Replaced by the size of the current input file. 1168 1169 %c Replaced by the column number of the text appearing in the first 1170 column of the screen. 1171 1172 %d[4mX[24m Replaced by the page number of a line in the input file. The 1173 line to be used is determined by the [4mX[24m, as with the %b option. 1174 1175 %D Replaced by the number of pages in the input file, or equiva- 1176 lently, the page number of the last line in the input file. 1177 1178 %E Replaced by the name of the editor (from the VISUAL environment 1179 variable, or the EDITOR environment variable if VISUAL is not 1180 defined). See the discussion of the LESSEDIT feature below. 1181 1182 %f Replaced by the name of the current input file. 1183 1184 %i Replaced by the index of the current file in the list of input 1185 files. 1186 1187 %l[4mX[24m Replaced by the line number of a line in the input file. The 1188 line to be used is determined by the [4mX[24m, as with the %b option. 1189 1190 %L Replaced by the line number of the last line in the input file. 1191 1192 %m Replaced by the total number of input files. 1193 1194 %p[4mX[24m Replaced by the percent into the current input file, based on 1195 byte offsets. The line used is determined by the [4mX[24m as with the 1196 %b option. 1197 1198 %P[4mX[24m Replaced by the percent into the current input file, based on 1199 line numbers. The line used is determined by the [4mX[24m as with the 1200 %b option. 1201 1202 %s Same as %B. 1203 1204 %t Causes any trailing spaces to be removed. Usually used at the 1205 end of the string, but may appear anywhere. 1206 1207 %x Replaced by the name of the next input file in the list. 1208 1209 If any item is unknown (for example, the file size if input is a pipe), 1210 a question mark is printed instead. 1211 1212 The format of the prompt string can be changed depending on certain 1213 conditions. A question mark followed by a single character acts like 1214 an "IF": depending on the following character, a condition is evalu- 1215 ated. If the condition is true, any characters following the question 1216 mark and condition character, up to a period, are included in the 1217 prompt. If the condition is false, such characters are not included. 1218 A colon appearing between the question mark and the period can be used 1219 to establish an "ELSE": any characters between the colon and the period 1220 are included in the string if and only if the IF condition is false. 1221 Condition characters (which follow a question mark) may be: 1222 1223 ?a True if any characters have been included in the prompt so far. 1224 1225 ?b[4mX[24m True if the byte offset of the specified line is known. 1226 1227 ?B True if the size of current input file is known. 1228 1229 ?c True if the text is horizontally shifted (%c is not zero). 1230 1231 ?d[4mX[24m True if the page number of the specified line is known. 1232 1233 ?e True if at end-of-file. 1234 1235 ?f True if there is an input filename (that is, if input is not a 1236 pipe). 1237 1238 ?l[4mX[24m True if the line number of the specified line is known. 1239 1240 ?L True if the line number of the last line in the file is known. 1241 1242 ?m True if there is more than one input file. 1243 1244 ?n True if this is the first prompt in a new input file. 1245 1246 ?p[4mX[24m True if the percent into the current input file, based on byte 1247 offsets, of the specified line is known. 1248 1249 ?P[4mX[24m True if the percent into the current input file, based on line 1250 numbers, of the specified line is known. 1251 1252 ?s Same as "?B". 1253 1254 ?x True if there is a next input file (that is, if the current 1255 input file is not the last one). 1256 1257 Any characters other than the special ones (question mark, colon, 1258 period, percent, and backslash) become literally part of the prompt. 1259 Any of the special characters may be included in the prompt literally 1260 by preceding it with a backslash. 1261 1262 Some examples: 1263 1264 ?f%f:Standard input. 1265 1266 This prompt prints the filename, if known; otherwise the string "Stan- 1267 dard input". 1268 1269 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-... 1270 1271 This prompt would print the filename, if known. The filename is fol- 1272 lowed by the line number, if known, otherwise the percent if known, 1273 otherwise the byte offset if known. Otherwise, a dash is printed. 1274 Notice how each question mark has a matching period, and how the % 1275 after the %pt is included literally by escaping it with a backslash. 1276 1277 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t 1278 1279 This prints the filename if this is the first prompt in a file, fol- 1280 lowed by the "file N of N" message if there is more than one input 1281 file. Then, if we are at end-of-file, the string "(END)" is printed 1282 followed by the name of the next file, if there is one. Finally, any 1283 trailing spaces are truncated. This is the default prompt. For refer- 1284 ence, here are the defaults for the other two prompts (-m and -M 1285 respectively). Each is broken into two lines here for readability 1286 only. 1287 1288 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.: 1289 ?pB%pB\%:byte %bB?s/%s...%t 1290 1291 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. : 1292 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t 1293 1294 And here is the default message produced by the = command: 1295 1296 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. . 1297 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t 1298 1299 The prompt expansion features are also used for another purpose: if an 1300 environment variable LESSEDIT is defined, it is used as the command to 1301 be executed when the v command is invoked. The LESSEDIT string is 1302 expanded in the same way as the prompt strings. The default value for 1303 LESSEDIT is: 1304 1305 %E ?lm+%lm. %f 1306 1307 Note that this expands to the editor name, followed by a + and the line 1308 number, followed by the file name. If your editor does not accept the 1309 "+linenumber" syntax, or has other differences in invocation syntax, 1310 the LESSEDIT variable can be changed to modify this default. 1311 1312 1313[1mSECURITY[0m 1314 When the environment variable LESSSECURE is set to 1, [4mless[24m runs in a 1315 "secure" mode. This means these features are disabled: 1316 1317 ! the shell command 1318 1319 | the pipe command 1320 1321 :e the examine command. 1322 1323 v the editing command 1324 1325 s -o log files 1326 1327 -k use of lesskey files 1328 1329 -t use of tags files 1330 1331 metacharacters in filenames, such as * 1332 1333 filename completion (TAB, ^L) 1334 1335 Less can also be compiled to be permanently in "secure" mode. 1336 1337 1338[1mCOMPATIBILITY WITH MORE[0m 1339 If the environment variable LESS_IS_MORE is set to 1, or if the program 1340 is invoked via a file link named "more", [4mless[24m behaves (mostly) in con- 1341 formance with the POSIX "more" command specification. In this mode, 1342 less behaves differently in these ways: 1343 1344 The -e option works differently. If the -e option is not set, [4mless[0m 1345 behaves as if the -E option were set. If the -e option is set, [4mless[0m 1346 behaves as if the -e and -F options were set. 1347 1348 The -m option works differently. If the -m option is not set, the 1349 medium prompt is used, and it is prefixed with the string "--More--". 1350 If the -m option is set, the short prompt is used. 1351 1352 The -n option acts like the -z option. The normal behavior of the -n 1353 option is unavailable in this mode. 1354 1355 The parameter to the -p option is taken to be a [4mless[24m command rather 1356 than a search pattern. 1357 1358 The LESS environment variable is ignored, and the MORE environment 1359 variable is used in its place. 1360 1361 1362[1mENVIRONMENT VARIABLES[0m 1363 Environment variables may be specified either in the system environment 1364 as usual, or in a [4mlesskey[24m (1) file. If environment variables are 1365 defined in more than one place, variables defined in a local lesskey 1366 file take precedence over variables defined in the system environment, 1367 which take precedence over variables defined in the system-wide lesskey 1368 file. 1369 1370 COLUMNS 1371 Sets the number of columns on the screen. Takes precedence over 1372 the number of columns specified by the TERM variable. (But if 1373 you have a windowing system which supports TIOCGWINSZ or 1374 WIOCGETD, the window system's idea of the screen size takes 1375 precedence over the LINES and COLUMNS environment variables.) 1376 1377 EDITOR The name of the editor (used for the v command). 1378 1379 HOME Name of the user's home directory (used to find a lesskey file 1380 on Unix and OS/2 systems). 1381 1382 HOMEDRIVE, HOMEPATH 1383 Concatenation of the HOMEDRIVE and HOMEPATH environment vari- 1384 ables is the name of the user's home directory if the HOME vari- 1385 able is not set (only in the Windows version). 1386 1387 INIT Name of the user's init directory (used to find a lesskey file 1388 on OS/2 systems). 1389 1390 LANG Language for determining the character set. 1391 1392 LC_CTYPE 1393 Language for determining the character set. 1394 1395 LESS Options which are passed to [4mless[24m automatically. 1396 1397 LESSANSIENDCHARS 1398 Characters which may end an ANSI color escape sequence (default 1399 "m"). 1400 1401 LESSANSIMIDCHARS 1402 Characters which may appear between the ESC character and the 1403 end character in an ANSI color escape sequence (default 1404 "0123456789;[?!"'#%()*+ ". 1405 1406 LESSBINFMT 1407 Format for displaying non-printable, non-control characters. 1408 1409 LESSCHARDEF 1410 Defines a character set. 1411 1412 LESSCHARSET 1413 Selects a predefined character set. 1414 1415 LESSCLOSE 1416 Command line to invoke the (optional) input-postprocessor. 1417 1418 LESSECHO 1419 Name of the lessecho program (default "lessecho"). The lessecho 1420 program is needed to expand metacharacters, such as * and ?, in 1421 filenames on Unix systems. 1422 1423 LESSEDIT 1424 Editor prototype string (used for the v command). See discus- 1425 sion under PROMPTS. 1426 1427 LESSGLOBALTAGS 1428 Name of the command used by the -t option to find global tags. 1429 Normally should be set to "global" if your system has the [4mglobal[0m 1430 (1) command. If not set, global tags are not used. 1431 1432 LESSHISTFILE 1433 Name of the history file used to remember search commands and 1434 shell commands between invocations of [4mless.[24m If set to "-" or 1435 "/dev/null", a history file is not used. The default is 1436 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and 1437 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini" 1438 on OS/2 systems. 1439 1440 LESSHISTSIZE 1441 The maximum number of commands to save in the history file. The 1442 default is 100. 1443 1444 LESSKEY 1445 Name of the default lesskey(1) file. 1446 1447 LESSKEY_SYSTEM 1448 Name of the default system-wide lesskey(1) file. 1449 1450 LESSMETACHARS 1451 List of characters which are considered "metacharacters" by the 1452 shell. 1453 1454 LESSMETAESCAPE 1455 Prefix which less will add before each metacharacter in a com- 1456 mand sent to the shell. If LESSMETAESCAPE is an empty string, 1457 commands containing metacharacters will not be passed to the 1458 shell. 1459 1460 LESSOPEN 1461 Command line to invoke the (optional) input-preprocessor. 1462 1463 LESSSECURE 1464 Runs less in "secure" mode. See discussion under SECURITY. 1465 1466 LESSSEPARATOR 1467 String to be appended to a directory name in filename comple- 1468 tion. 1469 1470 LESSUTFBINFMT 1471 Format for displaying non-printable Unicode code points. 1472 1473 LESS_IS_MORE 1474 Emulate the [4mmore[24m (1) command. 1475 1476 LINES Sets the number of lines on the screen. Takes precedence over 1477 the number of lines specified by the TERM variable. (But if you 1478 have a windowing system which supports TIOCGWINSZ or WIOCGETD, 1479 the window system's idea of the screen size takes precedence 1480 over the LINES and COLUMNS environment variables.) 1481 1482 PATH User's search path (used to find a lesskey file on MS-DOS and 1483 OS/2 systems). 1484 1485 SHELL The shell used to execute the ! command, as well as to expand 1486 filenames. 1487 1488 TERM The type of terminal on which [4mless[24m is being run. 1489 1490 VISUAL The name of the editor (used for the v command). 1491 1492 1493[1mSEE ALSO[0m 1494 lesskey(1) 1495 1496 1497[1mWARNINGS[0m 1498 The = command and prompts (unless changed by -P) report the line num- 1499 bers of the lines at the top and bottom of the screen, but the byte and 1500 percent of the line after the one at the bottom of the screen. 1501 1502 On certain older terminals (the so-called "magic cookie" terminals), 1503 search highlighting will cause an erroneous display. On such termi- 1504 nals, search highlighting is disabled by default to avoid possible 1505 problems. 1506 1507 When searching in a binary file, text which follows a null byte may not 1508 be found. This problem does not occur when searching with regular 1509 expressions turned off via ^R, and also does not occur when [4mless[24m is 1510 compiled to use the PCRE regular expression library. 1511 1512 In certain cases, when search highlighting is enabled and a search 1513 pattern begins with a ^, more text than the matching string may be 1514 highlighted. (This problem does not occur when less is compiled to use 1515 the POSIX regular expression package.) 1516 1517 On some systems, [4msetlocale[24m claims that ASCII characters 0 thru 31 are 1518 control characters rather than binary characters. This causes [4mless[24m to 1519 treat some binary files as ordinary, non-binary files. To workaround 1520 this problem, set the environment variable LESSCHARSET to "ascii" (or 1521 whatever character set is appropriate). 1522 1523 This manual is too long. 1524 1525 See http://www.greenwoodsoftware.com/less for the latest list of known 1526 bugs in less. 1527 1528 1529[1mCOPYRIGHT[0m 1530 Copyright (C) 1984-2007 Mark Nudelman 1531 1532 less is part of the GNU project and is free software. You can redis- 1533 tribute it and/or modify it under the terms of either (1) the GNU Gen- 1534 eral Public License as published by the Free Software Foundation; or 1535 (2) the Less License. See the file README in the less distribution for 1536 more details regarding redistribution. You should have received a copy 1537 of the GNU General Public License along with the source for less; see 1538 the file COPYING. If not, write to the Free Software Foundation, 59 1539 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also 1540 have received a copy of the Less License; see the file LICENSE. 1541 1542 less is distributed in the hope that it will be useful, but WITHOUT ANY 1543 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT- 1544 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 1545 more details. 1546 1547 1548[1mAUTHOR[0m 1549 Mark Nudelman <markn@greenwoodsoftware.com> 1550 Send bug reports or comments to the above address or to 1551 bug-less@gnu.org. 1552 For more information, see the less homepage at 1553 http://www.greenwoodsoftware.com/less. 1554 1555 1556 1557 Version 415: 15 Nov 2007 LESS(1) 1558