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 can be 449 read 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 piped data is kept in memory; any 460 earlier 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. The target line is the line specified by any com- 537 mand to search for a pattern, jump to a line number, jump to a 538 file percentage or jump to a tag. The screen line may be speci- 539 fied by a number: the top line on the screen is 1, the next is 540 2, and so on. The number may be negative to specify a line rel- 541 ative to the bottom of the screen: the bottom line on the screen 542 is -1, the second to the bottom is -2, and so on. Alternately, 543 the screen line may be specified as a fraction of the height of 544 the screen, starting with a decimal point: .5 is in the middle 545 of the screen, .3 is three tenths down from the first line, and 546 so 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 any form of the -j option is used, forward 550 searches begin at the line immediately after the target line, 551 and backward searches begin at the target line. For example, if 552 "-j4" is used, the target line is the fourth line on the screen, 553 so forward searches begin at the fifth line on the screen. 554 555 -J or --status-column 556 Displays a status column at the left edge of the screen. The 557 status column shows the lines that matched the current search. 558 The status column is also used if the -w or -W option is in 559 effect. 560 561 -k[4mfilename[24m or --lesskey-file=[4mfilename[0m 562 Causes [4mless[24m to open and interpret the named file as a [4mlesskey[0m 563 (1) file. Multiple -k options may be specified. If the LESSKEY 564 or LESSKEY_SYSTEM environment variable is set, or if a lesskey 565 file is found in a standard place (see KEY BINDINGS), it is also 566 used as a [4mlesskey[24m file. 567 568 -K or --quit-on-intr 569 Causes [4mless[24m to exit immediately when an interrupt character 570 (usually ^C) is typed. Normally, an interrupt character causes 571 [4mless[24m to stop whatever it is doing and return to its command 572 prompt. Note that use of this option makes it impossible to 573 return to the command prompt from the "F" command. 574 575 -L or --no-lessopen 576 Ignore the LESSOPEN environment variable (see the INPUT PREPRO- 577 CESSOR section below). This option can be set from within [4mless[24m, 578 but it will apply only to files opened subsequently, not to the 579 file which is currently open. 580 581 -m or --long-prompt 582 Causes [4mless[24m to prompt verbosely (like [4mmore[24m), with the percent 583 into the file. By default, [4mless[24m prompts with a colon. 584 585 -M or --LONG-PROMPT 586 Causes [4mless[24m to prompt even more verbosely than [4mmore.[0m 587 588 -n or --line-numbers 589 Suppresses line numbers. The default (to use line numbers) may 590 cause [4mless[24m to run more slowly in some cases, especially with a 591 very large input file. Suppressing line numbers with the -n 592 option will avoid this problem. Using line numbers means: the 593 line number will be displayed in the verbose prompt and in the = 594 command, and the v command will pass the current line number to 595 the editor (see also the discussion of LESSEDIT in PROMPTS 596 below). 597 598 -N or --LINE-NUMBERS 599 Causes a line number to be displayed at the beginning of each 600 line in the display. 601 602 -o[4mfilename[24m or --log-file=[4mfilename[0m 603 Causes [4mless[24m to copy its input to the named file as it is being 604 viewed. This applies only when the input file is a pipe, not an 605 ordinary file. If the file already exists, [4mless[24m will ask for 606 confirmation before overwriting it. 607 608 -O[4mfilename[24m or --LOG-FILE=[4mfilename[0m 609 The -O option is like -o, but it will overwrite an existing file 610 without asking for confirmation. 611 612 If no log file has been specified, the -o and -O options can be 613 used from within [4mless[24m to specify a log file. Without a file 614 name, they will simply report the name of the log file. The "s" 615 command is equivalent to specifying -o from within [4mless.[0m 616 617 -p[4mpattern[24m or --pattern=[4mpattern[0m 618 The -p option on the command line is equivalent to specifying 619 +/[4mpattern[24m; that is, it tells [4mless[24m to start at the first occur- 620 rence of [4mpattern[24m in the file. 621 622 -P[4mprompt[24m or --prompt=[4mprompt[0m 623 Provides a way to tailor the three prompt styles to your own 624 preference. This option would normally be put in the LESS envi- 625 ronment variable, rather than being typed in with each [4mless[24m com- 626 mand. Such an option must either be the last option in the LESS 627 variable, or be terminated by a dollar sign. -Ps followed by a 628 string changes the default (short) prompt to that string. -Pm 629 changes the medium (-m) prompt. -PM changes the long (-M) 630 prompt. -Ph changes the prompt for the help screen. -P= 631 changes the message printed by the = command. -Pw changes the 632 message printed while waiting for data (in the F command). All 633 prompt strings consist of a sequence of letters and special 634 escape sequences. See the section on PROMPTS for more details. 635 636 -q or --quiet or --silent 637 Causes moderately "quiet" operation: the terminal bell is not 638 rung if an attempt is made to scroll past the end of the file or 639 before the beginning of the file. If the terminal has a "visual 640 bell", it is used instead. The bell will be rung on certain 641 other errors, such as typing an invalid character. The default 642 is to ring the terminal bell in all such cases. 643 644 -Q or --QUIET or --SILENT 645 Causes totally "quiet" operation: the terminal bell is never 646 rung. 647 648 -r or --raw-control-chars 649 Causes "raw" control characters to be displayed. The default is 650 to display control characters using the caret notation; for 651 example, a control-A (octal 001) is displayed as "^A". Warning: 652 when the -r option is used, [4mless[24m cannot keep track of the actual 653 appearance of the screen (since this depends on how the screen 654 responds to each type of control character). Thus, various dis- 655 play problems may result, such as long lines being split in the 656 wrong place. 657 658 -R or --RAW-CONTROL-CHARS 659 Like -r, but only ANSI "color" escape sequences are output in 660 "raw" form. Unlike -r, the screen appearance is maintained cor- 661 rectly in most cases. ANSI "color" escape sequences are 662 sequences of the form: 663 664 ESC [ ... m 665 666 where the "..." is zero or more color specification characters 667 For the purpose of keeping track of screen appearance, ANSI 668 color escape sequences are assumed to not move the cursor. You 669 can make [4mless[24m think that characters other than "m" can end ANSI 670 color escape sequences by setting the environment variable 671 LESSANSIENDCHARS to the list of characters which can end a color 672 escape sequence. And you can make [4mless[24m think that characters 673 other than the standard ones may appear between the ESC and the 674 m by setting the environment variable LESSANSIMIDCHARS to the 675 list of characters which can appear. 676 677 -s or --squeeze-blank-lines 678 Causes consecutive blank lines to be squeezed into a single 679 blank line. This is useful when viewing [4mnroff[24m output. 680 681 -S or --chop-long-lines 682 Causes lines longer than the screen width to be chopped rather 683 than folded. That is, the portion of a long line that does not 684 fit in the screen width is not shown. The default is to fold 685 long lines; that is, display the remainder on the next line. 686 687 -t[4mtag[24m or --tag=[4mtag[0m 688 The -t option, followed immediately by a TAG, will edit the file 689 containing that tag. For this to work, tag information must be 690 available; for example, there may be a file in the current 691 directory called "tags", which was previously built by [4mctags[24m (1) 692 or an equivalent command. If the environment variable LESSGLOB- 693 ALTAGS is set, it is taken to be the name of a command compati- 694 ble with [4mglobal[24m (1), and that command is executed to find the 695 tag. (See http://www.gnu.org/software/global/global.html). The 696 -t option may also be specified from within [4mless[24m (using the - 697 command) as a way of examining a new file. The command ":t" is 698 equivalent to specifying -t from within [4mless.[0m 699 700 -T[4mtagsfile[24m or --tag-file=[4mtagsfile[0m 701 Specifies a tags file to be used instead of "tags". 702 703 -u or --underline-special 704 Causes backspaces and carriage returns to be treated as print- 705 able characters; that is, they are sent to the terminal when 706 they appear in the input. 707 708 -U or --UNDERLINE-SPECIAL 709 Causes backspaces, tabs and carriage returns to be treated as 710 control characters; that is, they are handled as specified by 711 the -r option. 712 713 By default, if neither -u nor -U is given, backspaces which 714 appear adjacent to an underscore character are treated spe- 715 cially: the underlined text is displayed using the terminal's 716 hardware underlining capability. Also, backspaces which appear 717 between two identical characters are treated specially: the 718 overstruck text is printed using the terminal's hardware bold- 719 face capability. Other backspaces are deleted, along with the 720 preceding character. Carriage returns immediately followed by a 721 newline are deleted. other carriage returns are handled as 722 specified by the -r option. Text which is overstruck or under- 723 lined can be searched for if neither -u nor -U is in effect. 724 725 -V or --version 726 Displays the version number of [4mless.[0m 727 728 -w or --hilite-unread 729 Temporarily highlights the first "new" line after a forward 730 movement of a full page. The first "new" line is the line imme- 731 diately following the line previously at the bottom of the 732 screen. Also highlights the target line after a g or p command. 733 The highlight is removed at the next command which causes move- 734 ment. The entire line is highlighted, unless the -J option is 735 in effect, in which case only the status column is highlighted. 736 737 -W or --HILITE-UNREAD 738 Like -w, but temporarily highlights the first new line after any 739 forward movement command larger than one line. 740 741 -x[4mn[24m,... or --tabs=[4mn[24m,... 742 Sets tab stops. If only one [4mn[24m is specified, tab stops are set 743 at multiples of [4mn[24m. If multiple values separated by commas are 744 specified, tab stops are set at those positions, and then con- 745 tinue with the same spacing as the last two. For example, 746 [4m-x9,17[24m will set tabs at positions 9, 17, 25, 33, etc. The 747 default for [4mn[24m is 8. 748 749 -X or --no-init 750 Disables sending the termcap initialization and deinitialization 751 strings to the terminal. This is sometimes desirable if the 752 deinitialization string does something unnecessary, like clear- 753 ing the screen. 754 755 -y[4mn[24m or --max-forw-scroll=[4mn[0m 756 Specifies a maximum number of lines to scroll forward. If it is 757 necessary to scroll forward more than [4mn[24m lines, the screen is 758 repainted instead. The -c or -C option may be used to repaint 759 from the top of the screen if desired. By default, any forward 760 movement causes scrolling. 761 762 -[z][4mn[24m or --window=[4mn[0m 763 Changes the default scrolling window size to [4mn[24m lines. The 764 default is one screenful. The z and w commands can also be used 765 to change the window size. The "z" may be omitted for compati- 766 bility with some versions of [4mmore.[24m If the number [4mn[24m is negative, 767 it indicates [4mn[24m lines less than the current screen size. For 768 example, if the screen is 24 lines, [4m-z-4[24m sets the scrolling win- 769 dow to 20 lines. If the screen is resized to 40 lines, the 770 scrolling window automatically changes to 36 lines. 771 772 -[4m"cc[24m or --quotes=[4mcc[0m 773 Changes the filename quoting character. This may be necessary 774 if you are trying to name a file which contains both spaces and 775 quote characters. Followed by a single character, this changes 776 the quote character to that character. Filenames containing a 777 space should then be surrounded by that character rather than by 778 double quotes. Followed by two characters, changes the open 779 quote to the first character, and the close quote to the second 780 character. Filenames containing a space should then be preceded 781 by the open quote character and followed by the close quote 782 character. Note that even after the quote characters are 783 changed, this option remains -" (a dash followed by a double 784 quote). 785 786 -~ or --tilde 787 Normally lines after end of file are displayed as a single tilde 788 (~). This option causes lines after end of file to be displayed 789 as blank lines. 790 791 -# or --shift 792 Specifies the default number of positions to scroll horizontally 793 in the RIGHTARROW and LEFTARROW commands. If the number speci- 794 fied is zero, it sets the default number of positions to one 795 half of the screen width. 796 797 --no-keypad 798 Disables sending the keypad initialization and deinitialization 799 strings to the terminal. This is sometimes useful if the keypad 800 strings make the numeric keypad behave in an undesirable manner. 801 802 --follow-name 803 Normally, if the input file is renamed while an F command is 804 executing, [4mless[24m will continue to display the contents of the 805 original file despite its name change. If --follow-name is 806 specified, during an F command [4mless[24m will periodically attempt to 807 reopen the file by name. If the reopen succeeds and the file is 808 a different file from the original (which means that a new file 809 has been created with the same name as the original (now 810 renamed) file), [4mless[24m will display the contents of that new file. 811 812 -- A command line argument of "--" marks the end of option argu- 813 ments. Any arguments following this are interpreted as file- 814 names. This can be useful when viewing a file whose name begins 815 with a "-" or "+". 816 817 + If a command line option begins with [1m+[22m, the remainder of that 818 option is taken to be an initial command to [4mless.[24m For example, 819 +G tells [4mless[24m to start at the end of the file rather than the 820 beginning, and +/xyz tells it to start at the first occurrence 821 of "xyz" in the file. As a special case, +<number> acts like 822 +<number>g; that is, it starts the display at the specified line 823 number (however, see the caveat under the "g" command above). 824 If the option starts with ++, the initial command applies to 825 every file being viewed, not just the first one. The + command 826 described previously may also be used to set (or change) an ini- 827 tial command for every file. 828 829 830[1mLINE EDITING[0m 831 When entering command line at the bottom of the screen (for example, a 832 filename for the :e command, or the pattern for a search command), cer- 833 tain keys can be used to manipulate the command line. Most commands 834 have an alternate form in [ brackets ] which can be used if a key does 835 not exist on a particular keyboard. (Note that the forms beginning 836 with ESC do not work in some MS-DOS and Windows systems because ESC is 837 the line erase character.) Any of these special keys may be entered 838 literally by preceding it with the "literal" character, either ^V or 839 ^A. A backslash itself may also be entered literally by entering two 840 backslashes. 841 842 LEFTARROW [ ESC-h ] 843 Move the cursor one space to the left. 844 845 RIGHTARROW [ ESC-l ] 846 Move the cursor one space to the right. 847 848 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ] 849 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur- 850 sor one word to the left. 851 852 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ] 853 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur- 854 sor one word to the right. 855 856 HOME [ ESC-0 ] 857 Move the cursor to the beginning of the line. 858 859 END [ ESC-$ ] 860 Move the cursor to the end of the line. 861 862 BACKSPACE 863 Delete the character to the left of the cursor, or cancel the 864 command if the command line is empty. 865 866 DELETE or [ ESC-x ] 867 Delete the character under the cursor. 868 869 ^BACKSPACE [ ESC-BACKSPACE ] 870 (That is, CONTROL and BACKSPACE simultaneously.) Delete the 871 word to the left of the cursor. 872 873 ^DELETE [ ESC-X or ESC-DELETE ] 874 (That is, CONTROL and DELETE simultaneously.) Delete the word 875 under the cursor. 876 877 UPARROW [ ESC-k ] 878 Retrieve the previous command line. 879 880 DOWNARROW [ ESC-j ] 881 Retrieve the next command line. 882 883 TAB Complete the partial filename to the left of the cursor. If it 884 matches more than one filename, the first match is entered into 885 the command line. Repeated TABs will cycle thru the other 886 matching filenames. If the completed filename is a directory, a 887 "/" is appended to the filename. (On MS-DOS systems, a "\" is 888 appended.) The environment variable LESSSEPARATOR can be used 889 to specify a different character to append to a directory name. 890 891 BACKTAB [ ESC-TAB ] 892 Like, TAB, but cycles in the reverse direction thru the matching 893 filenames. 894 895 ^L Complete the partial filename to the left of the cursor. If it 896 matches more than one filename, all matches are entered into the 897 command line (if they fit). 898 899 ^U (Unix and OS/2) or ESC (MS-DOS) 900 Delete the entire command line, or cancel the command if the 901 command line is empty. If you have changed your line-kill char- 902 acter in Unix to something other than ^U, that character is used 903 instead of ^U. 904 905 906[1mKEY BINDINGS[0m 907 You may define your own [4mless[24m commands by using the program [4mlesskey[24m (1) 908 to create a lesskey file. This file specifies a set of command keys 909 and an action associated with each key. You may also use [4mlesskey[24m to 910 change the line-editing keys (see LINE EDITING), and to set environment 911 variables. If the environment variable LESSKEY is set, [4mless[24m uses that 912 as the name of the lesskey file. Otherwise, [4mless[24m looks in a standard 913 place for the lesskey file: On Unix systems, [4mless[24m looks for a lesskey 914 file called "$HOME/.less". On MS-DOS and Windows systems, [4mless[24m looks 915 for a lesskey file called "$HOME/_less", and if it is not found there, 916 then looks for a lesskey file called "_less" in any directory specified 917 in the PATH environment variable. On OS/2 systems, [4mless[24m looks for a 918 lesskey file called "$HOME/less.ini", and if it is not found, then 919 looks for a lesskey file called "less.ini" in any directory specified 920 in the INIT environment variable, and if it not found there, then looks 921 for a lesskey file called "less.ini" in any directory specified in the 922 PATH environment variable. See the [4mlesskey[24m manual page for more 923 details. 924 925 A system-wide lesskey file may also be set up to provide key bindings. 926 If a key is defined in both a local lesskey file and in the system-wide 927 file, key bindings in the local file take precedence over those in the 928 system-wide file. If the environment variable LESSKEY_SYSTEM is set, 929 [4mless[24m uses that as the name of the system-wide lesskey file. Otherwise, 930 [4mless[24m looks in a standard place for the system-wide lesskey file: On 931 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. 932 (However, if [4mless[24m was built with a different sysconf directory than 933 /usr/local/etc, that directory is where the sysless file is found.) On 934 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys- 935 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini. 936 937 938[1mINPUT PREPROCESSOR[0m 939 You may define an "input preprocessor" for [4mless.[24m Before [4mless[24m opens a 940 file, it first gives your input preprocessor a chance to modify the way 941 the contents of the file are displayed. An input preprocessor is sim- 942 ply an executable program (or shell script), which writes the contents 943 of the file to a different file, called the replacement file. The con- 944 tents of the replacement file are then displayed in place of the con- 945 tents of the original file. However, it will appear to the user as if 946 the original file is opened; that is, [4mless[24m will display the original 947 filename as the name of the current file. 948 949 An input preprocessor receives one command line argument, the original 950 filename, as entered by the user. It should create the replacement 951 file, and when finished, print the name of the replacement file to its 952 standard output. If the input preprocessor does not output a replace- 953 ment filename, [4mless[24m uses the original file, as normal. The input pre- 954 processor is not called when viewing standard input. To set up an 955 input preprocessor, set the LESSOPEN environment variable to a command 956 line which will invoke your input preprocessor. This command line 957 should include one occurrence of the string "%s", which will be 958 replaced by the filename when the input preprocessor command is 959 invoked. 960 961 When [4mless[24m closes a file opened in such a way, it will call another pro- 962 gram, called the input postprocessor, which may perform any desired 963 clean-up action (such as deleting the replacement file created by 964 LESSOPEN). This program receives two command line arguments, the orig- 965 inal filename as entered by the user, and the name of the replacement 966 file. To set up an input postprocessor, set the LESSCLOSE environment 967 variable to a command line which will invoke your input postprocessor. 968 It may include two occurrences of the string "%s"; the first is 969 replaced with the original name of the file and the second with the 970 name of the replacement file, which was output by LESSOPEN. 971 972 For example, on many Unix systems, these two scripts will allow you to 973 keep files in compressed format, but still let [4mless[24m view them directly: 974 975 lessopen.sh: 976 #! /bin/sh 977 case "$1" in 978 *.Z) uncompress - 979 if [ -s /tmp/less.$$ ]; then 980 echo /tmp/less.$$ 981 else 982 rm -f /tmp/less.$$ 983 fi 984 ;; 985 esac 986 987 lessclose.sh: 988 #! /bin/sh 989 rm $2 990 991 To use these scripts, put them both where they can be executed and set 992 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More 993 complex LESSOPEN and LESSCLOSE scripts may be written to accept other 994 types of compressed files, and so on. 995 996 It is also possible to set up an input preprocessor to pipe the file 997 data directly to [4mless,[24m rather than putting the data into a replacement 998 file. This avoids the need to decompress the entire file before start- 999 ing to view it. An input preprocessor that works this way is called an 1000 input pipe. An input pipe, instead of writing the name of a replace- 1001 ment file on its standard output, writes the entire contents of the 1002 replacement file on its standard output. If the input pipe does not 1003 write any characters on its standard output, then there is no replace- 1004 ment file and [4mless[24m uses the original file, as normal. To use an input 1005 pipe, make the first character in the LESSOPEN environment variable a 1006 vertical bar (|) to signify that the input preprocessor is an input 1007 pipe. 1008 1009 For example, on many Unix systems, this script will work like the pre- 1010 vious example scripts: 1011 1012 lesspipe.sh: 1013 #! /bin/sh 1014 case "$1" in 1015 *.Z) uncompress -c $1 2>/dev/null 1016 ;; 1017 esac 1018 1019 To use this script, put it where it can be executed and set 1020 LESSOPEN="|lesspipe.sh %s". When an input pipe is used, a LESSCLOSE 1021 postprocessor can be used, but it is usually not necessary since there 1022 is no replacement file to clean up. In this case, the replacement file 1023 name passed to the LESSCLOSE postprocessor is "-". 1024 1025 1026[1mNATIONAL CHARACTER SETS[0m 1027 There are three types of characters in the input file: 1028 1029 normal characters 1030 can be displayed directly to the screen. 1031 1032 control characters 1033 should not be displayed directly, but are expected to be found 1034 in ordinary text files (such as backspace and tab). 1035 1036 binary characters 1037 should not be displayed directly and are not expected to be 1038 found in text files. 1039 1040 A "character set" is simply a description of which characters are to be 1041 considered normal, control, and binary. The LESSCHARSET environment 1042 variable may be used to select a character set. Possible values for 1043 LESSCHARSET are: 1044 1045 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars 1046 with values between 32 and 126 are normal, and all others are 1047 binary. 1048 1049 iso8859 1050 Selects an ISO 8859 character set. This is the same as ASCII, 1051 except characters between 160 and 255 are treated as normal 1052 characters. 1053 1054 latin1 Same as iso8859. 1055 1056 latin9 Same as iso8859. 1057 1058 dos Selects a character set appropriate for MS-DOS. 1059 1060 ebcdic Selects an EBCDIC character set. 1061 1062 IBM-1047 1063 Selects an EBCDIC character set used by OS/390 Unix Services. 1064 This is the EBCDIC analogue of latin1. You get similar results 1065 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your 1066 environment. 1067 1068 koi8-r Selects a Russian character set. 1069 1070 next Selects a character set appropriate for NeXT computers. 1071 1072 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. 1073 UTF-8 is special in that it supports multi-byte characters in 1074 the input file. It is the only character set that supports 1075 multi-byte characters. 1076 1077 windows 1078 Selects a character set appropriate for Microsoft Windows (cp 1079 1251). 1080 1081 In rare cases, it may be desired to tailor [4mless[24m to use a character set 1082 other than the ones definable by LESSCHARSET. In this case, the envi- 1083 ronment variable LESSCHARDEF can be used to define a character set. It 1084 should be set to a string where each character in the string represents 1085 one character in the character set. The character "." is used for a 1086 normal character, "c" for control, and "b" for binary. A decimal num- 1087 ber may be used for repetition. For example, "bccc4b." would mean 1088 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are 1089 binary, and 8 is normal. All characters after the last are taken to be 1090 the same as the last, so characters 9 through 255 would be normal. 1091 (This is an example, and does not necessarily represent any real char- 1092 acter set.) 1093 1094 This table shows the value of LESSCHARDEF which is equivalent to each 1095 of the possible values for LESSCHARSET: 1096 1097 ascii 8bcccbcc18b95.b 1098 dos 8bcccbcc12bc5b95.b. 1099 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b 1100 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b. 1101 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc 1102 191.b 1103 iso8859 8bcccbcc18b95.33b. 1104 koi8-r 8bcccbcc18b95.b128. 1105 latin1 8bcccbcc18b95.33b. 1106 next 8bcccbcc18b95.bb125.bb 1107 1108 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings 1109 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_TYPE or 1110 LANG environment variables, then the default character set is utf-8. 1111 1112 If that string is not found, but your system supports the [4msetlocale[0m 1113 interface, [4mless[24m will use setlocale to determine the character set. 1114 setlocale is controlled by setting the LANG or LC_CTYPE environment 1115 variables. 1116 1117 Finally, if the [4msetlocale[24m interface is also not available, the default 1118 character set is latin1. 1119 1120 Control and binary characters are displayed in standout (reverse 1121 video). Each such character is displayed in caret notation if possible 1122 (e.g. ^A for control-A). Caret notation is used only if inverting the 1123 0100 bit results in a normal printable character. Otherwise, the char- 1124 acter is displayed as a hex number in angle brackets. This format can 1125 be changed by setting the LESSBINFMT environment variable. LESSBINFMT 1126 may begin with a "*" and one character to select the display attribute: 1127 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout, 1128 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal 1129 attribute is assumed. The remainder of LESSBINFMT is a string which 1130 may include one printf-style escape sequence (a % followed by x, X, o, 1131 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters 1132 are displayed in underlined hexadecimal surrounded by brackets. The 1133 default if no LESSBINFMT is specified is "*s<%X>". The default if no 1134 LESSBINFMT is specified is "*s<%02X>". Warning: the result of expand- 1135 ing the character via LESSBINFMT must be less than 31 characters. 1136 1137 When the character set is utf-8, the LESSUTFBINFMT environment variable 1138 acts similarly to LESSBINFMT but it applies to Unicode code points that 1139 were successfully decoded but are unsuitable for display (e.g., unas- 1140 signed code points). Its default value is "<U+%04lX>". Note that 1141 LESSUTFBINFMT and LESSBINFMT share their display attribute setting 1142 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after 1143 LESSBINFMT so its setting, if any, will have priority. Problematic 1144 octets in a UTF-8 file (octets of a truncated sequence, octets of a 1145 complete but non-shortest form sequence, illegal octets, and stray 1146 trailing octets) are displayed individually using LESSBINFMT so as to 1147 facilitate diagnostic of how the UTF-8 file is ill-formed. 1148 1149 1150[1mPROMPTS[0m 1151 The -P option allows you to tailor the prompt to your preference. The 1152 string given to the -P option replaces the specified prompt string. 1153 Certain characters in the string are interpreted specially. The prompt 1154 mechanism is rather complicated to provide flexibility, but the ordi- 1155 nary user need not understand the details of constructing personalized 1156 prompt strings. 1157 1158 A percent sign followed by a single character is expanded according to 1159 what the following character is: 1160 1161 %b[4mX[24m Replaced by the byte offset into the current input file. The b 1162 is followed by a single character (shown as [4mX[24m above) which spec- 1163 ifies the line whose byte offset is to be used. If the charac- 1164 ter is a "t", the byte offset of the top line in the display is 1165 used, an "m" means use the middle line, a "b" means use the bot- 1166 tom line, a "B" means use the line just after the bottom line, 1167 and a "j" means use the "target" line, as specified by the -j 1168 option. 1169 1170 %B Replaced by the size of the current input file. 1171 1172 %c Replaced by the column number of the text appearing in the first 1173 column of the screen. 1174 1175 %d[4mX[24m Replaced by the page number of a line in the input file. The 1176 line to be used is determined by the [4mX[24m, as with the %b option. 1177 1178 %D Replaced by the number of pages in the input file, or equiva- 1179 lently, the page number of the last line in the input file. 1180 1181 %E Replaced by the name of the editor (from the VISUAL environment 1182 variable, or the EDITOR environment variable if VISUAL is not 1183 defined). See the discussion of the LESSEDIT feature below. 1184 1185 %f Replaced by the name of the current input file. 1186 1187 %i Replaced by the index of the current file in the list of input 1188 files. 1189 1190 %l[4mX[24m Replaced by the line number of a line in the input file. The 1191 line to be used is determined by the [4mX[24m, as with the %b option. 1192 1193 %L Replaced by the line number of the last line in the input file. 1194 1195 %m Replaced by the total number of input files. 1196 1197 %p[4mX[24m Replaced by the percent into the current input file, based on 1198 byte offsets. The line used is determined by the [4mX[24m as with the 1199 %b option. 1200 1201 %P[4mX[24m Replaced by the percent into the current input file, based on 1202 line numbers. The line used is determined by the [4mX[24m as with the 1203 %b option. 1204 1205 %s Same as %B. 1206 1207 %t Causes any trailing spaces to be removed. Usually used at the 1208 end of the string, but may appear anywhere. 1209 1210 %x Replaced by the name of the next input file in the list. 1211 1212 If any item is unknown (for example, the file size if input is a pipe), 1213 a question mark is printed instead. 1214 1215 The format of the prompt string can be changed depending on certain 1216 conditions. A question mark followed by a single character acts like 1217 an "IF": depending on the following character, a condition is evalu- 1218 ated. If the condition is true, any characters following the question 1219 mark and condition character, up to a period, are included in the 1220 prompt. If the condition is false, such characters are not included. 1221 A colon appearing between the question mark and the period can be used 1222 to establish an "ELSE": any characters between the colon and the period 1223 are included in the string if and only if the IF condition is false. 1224 Condition characters (which follow a question mark) may be: 1225 1226 ?a True if any characters have been included in the prompt so far. 1227 1228 ?b[4mX[24m True if the byte offset of the specified line is known. 1229 1230 ?B True if the size of current input file is known. 1231 1232 ?c True if the text is horizontally shifted (%c is not zero). 1233 1234 ?d[4mX[24m True if the page number of the specified line is known. 1235 1236 ?e True if at end-of-file. 1237 1238 ?f True if there is an input filename (that is, if input is not a 1239 pipe). 1240 1241 ?l[4mX[24m True if the line number of the specified line is known. 1242 1243 ?L True if the line number of the last line in the file is known. 1244 1245 ?m True if there is more than one input file. 1246 1247 ?n True if this is the first prompt in a new input file. 1248 1249 ?p[4mX[24m True if the percent into the current input file, based on byte 1250 offsets, of the specified line is known. 1251 1252 ?P[4mX[24m True if the percent into the current input file, based on line 1253 numbers, of the specified line is known. 1254 1255 ?s Same as "?B". 1256 1257 ?x True if there is a next input file (that is, if the current 1258 input file is not the last one). 1259 1260 Any characters other than the special ones (question mark, colon, 1261 period, percent, and backslash) become literally part of the prompt. 1262 Any of the special characters may be included in the prompt literally 1263 by preceding it with a backslash. 1264 1265 Some examples: 1266 1267 ?f%f:Standard input. 1268 1269 This prompt prints the filename, if known; otherwise the string "Stan- 1270 dard input". 1271 1272 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-... 1273 1274 This prompt would print the filename, if known. The filename is fol- 1275 lowed by the line number, if known, otherwise the percent if known, 1276 otherwise the byte offset if known. Otherwise, a dash is printed. 1277 Notice how each question mark has a matching period, and how the % 1278 after the %pt is included literally by escaping it with a backslash. 1279 1280 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t 1281 1282 This prints the filename if this is the first prompt in a file, fol- 1283 lowed by the "file N of N" message if there is more than one input 1284 file. Then, if we are at end-of-file, the string "(END)" is printed 1285 followed by the name of the next file, if there is one. Finally, any 1286 trailing spaces are truncated. This is the default prompt. For refer- 1287 ence, here are the defaults for the other two prompts (-m and -M 1288 respectively). Each is broken into two lines here for readability 1289 only. 1290 1291 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.: 1292 ?pB%pB\%:byte %bB?s/%s...%t 1293 1294 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. : 1295 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t 1296 1297 And here is the default message produced by the = command: 1298 1299 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. . 1300 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t 1301 1302 The prompt expansion features are also used for another purpose: if an 1303 environment variable LESSEDIT is defined, it is used as the command to 1304 be executed when the v command is invoked. The LESSEDIT string is 1305 expanded in the same way as the prompt strings. The default value for 1306 LESSEDIT is: 1307 1308 %E ?lm+%lm. %f 1309 1310 Note that this expands to the editor name, followed by a + and the line 1311 number, followed by the file name. If your editor does not accept the 1312 "+linenumber" syntax, or has other differences in invocation syntax, 1313 the LESSEDIT variable can be changed to modify this default. 1314 1315 1316[1mSECURITY[0m 1317 When the environment variable LESSSECURE is set to 1, [4mless[24m runs in a 1318 "secure" mode. This means these features are disabled: 1319 1320 ! the shell command 1321 1322 | the pipe command 1323 1324 :e the examine command. 1325 1326 v the editing command 1327 1328 s -o log files 1329 1330 -k use of lesskey files 1331 1332 -t use of tags files 1333 1334 metacharacters in filenames, such as * 1335 1336 filename completion (TAB, ^L) 1337 1338 Less can also be compiled to be permanently in "secure" mode. 1339 1340 1341[1mCOMPATIBILITY WITH MORE[0m 1342 If the environment variable LESS_IS_MORE is set to 1, or if the program 1343 is invoked via a file link named "more", [4mless[24m behaves (mostly) in con- 1344 formance with the POSIX "more" command specification. In this mode, 1345 less behaves differently in these ways: 1346 1347 The -e option works differently. If the -e option is not set, [4mless[0m 1348 behaves as if the -E option were set. If the -e option is set, [4mless[0m 1349 behaves as if the -e and -F options were set. 1350 1351 The -m option works differently. If the -m option is not set, the 1352 medium prompt is used, and it is prefixed with the string "--More--". 1353 If the -m option is set, the short prompt is used. 1354 1355 The -n option acts like the -z option. The normal behavior of the -n 1356 option is unavailable in this mode. 1357 1358 The parameter to the -p option is taken to be a [4mless[24m command rather 1359 than a search pattern. 1360 1361 The LESS environment variable is ignored, and the MORE environment 1362 variable is used in its place. 1363 1364 1365[1mENVIRONMENT VARIABLES[0m 1366 Environment variables may be specified either in the system environment 1367 as usual, or in a [4mlesskey[24m (1) file. If environment variables are 1368 defined in more than one place, variables defined in a local lesskey 1369 file take precedence over variables defined in the system environment, 1370 which take precedence over variables defined in the system-wide lesskey 1371 file. 1372 1373 COLUMNS 1374 Sets the number of columns on the screen. Takes precedence over 1375 the number of columns specified by the TERM variable. (But if 1376 you have a windowing system which supports TIOCGWINSZ or 1377 WIOCGETD, the window system's idea of the screen size takes 1378 precedence over the LINES and COLUMNS environment variables.) 1379 1380 EDITOR The name of the editor (used for the v command). 1381 1382 HOME Name of the user's home directory (used to find a lesskey file 1383 on Unix and OS/2 systems). 1384 1385 HOMEDRIVE, HOMEPATH 1386 Concatenation of the HOMEDRIVE and HOMEPATH environment vari- 1387 ables is the name of the user's home directory if the HOME vari- 1388 able is not set (only in the Windows version). 1389 1390 INIT Name of the user's init directory (used to find a lesskey file 1391 on OS/2 systems). 1392 1393 LANG Language for determining the character set. 1394 1395 LC_CTYPE 1396 Language for determining the character set. 1397 1398 LESS Options which are passed to [4mless[24m automatically. 1399 1400 LESSANSIENDCHARS 1401 Characters which may end an ANSI color escape sequence (default 1402 "m"). 1403 1404 LESSANSIMIDCHARS 1405 Characters which may appear between the ESC character and the 1406 end character in an ANSI color escape sequence (default 1407 "0123456789;[?!"'#%()*+ ". 1408 1409 LESSBINFMT 1410 Format for displaying non-printable, non-control characters. 1411 1412 LESSCHARDEF 1413 Defines a character set. 1414 1415 LESSCHARSET 1416 Selects a predefined character set. 1417 1418 LESSCLOSE 1419 Command line to invoke the (optional) input-postprocessor. 1420 1421 LESSECHO 1422 Name of the lessecho program (default "lessecho"). The lessecho 1423 program is needed to expand metacharacters, such as * and ?, in 1424 filenames on Unix systems. 1425 1426 LESSEDIT 1427 Editor prototype string (used for the v command). See discus- 1428 sion under PROMPTS. 1429 1430 LESSGLOBALTAGS 1431 Name of the command used by the -t option to find global tags. 1432 Normally should be set to "global" if your system has the [4mglobal[0m 1433 (1) command. If not set, global tags are not used. 1434 1435 LESSHISTFILE 1436 Name of the history file used to remember search commands and 1437 shell commands between invocations of [4mless.[24m If set to "-" or 1438 "/dev/null", a history file is not used. The default is 1439 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and 1440 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini" 1441 on OS/2 systems. 1442 1443 LESSHISTSIZE 1444 The maximum number of commands to save in the history file. The 1445 default is 100. 1446 1447 LESSKEY 1448 Name of the default lesskey(1) file. 1449 1450 LESSKEY_SYSTEM 1451 Name of the default system-wide lesskey(1) file. 1452 1453 LESSMETACHARS 1454 List of characters which are considered "metacharacters" by the 1455 shell. 1456 1457 LESSMETAESCAPE 1458 Prefix which less will add before each metacharacter in a com- 1459 mand sent to the shell. If LESSMETAESCAPE is an empty string, 1460 commands containing metacharacters will not be passed to the 1461 shell. 1462 1463 LESSOPEN 1464 Command line to invoke the (optional) input-preprocessor. 1465 1466 LESSSECURE 1467 Runs less in "secure" mode. See discussion under SECURITY. 1468 1469 LESSSEPARATOR 1470 String to be appended to a directory name in filename comple- 1471 tion. 1472 1473 LESSUTFBINFMT 1474 Format for displaying non-printable Unicode code points. 1475 1476 LESS_IS_MORE 1477 Emulate the [4mmore[24m (1) command. 1478 1479 LINES Sets the number of lines on the screen. Takes precedence over 1480 the number of lines specified by the TERM variable. (But if you 1481 have a windowing system which supports TIOCGWINSZ or WIOCGETD, 1482 the window system's idea of the screen size takes precedence 1483 over the LINES and COLUMNS environment variables.) 1484 1485 PATH User's search path (used to find a lesskey file on MS-DOS and 1486 OS/2 systems). 1487 1488 SHELL The shell used to execute the ! command, as well as to expand 1489 filenames. 1490 1491 TERM The type of terminal on which [4mless[24m is being run. 1492 1493 VISUAL The name of the editor (used for the v command). 1494 1495 1496[1mSEE ALSO[0m 1497 lesskey(1) 1498 1499 1500[1mCOPYRIGHT[0m 1501 Copyright (C) 1984-2007 Mark Nudelman 1502 1503 less is part of the GNU project and is free software. You can redis- 1504 tribute it and/or modify it under the terms of either (1) the GNU Gen- 1505 eral Public License as published by the Free Software Foundation; or 1506 (2) the Less License. See the file README in the less distribution for 1507 more details regarding redistribution. You should have received a copy 1508 of the GNU General Public License along with the source for less; see 1509 the file COPYING. If not, write to the Free Software Foundation, 59 1510 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also 1511 have received a copy of the Less License; see the file LICENSE. 1512 1513 less is distributed in the hope that it will be useful, but WITHOUT ANY 1514 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT- 1515 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 1516 more details. 1517 1518 1519[1mAUTHOR[0m 1520 Mark Nudelman <markn@greenwoodsoftware.com> 1521 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list 1522 of known bugs in less. 1523 Send bug reports or comments to the above address or to 1524 bug-less@gnu.org. 1525 For more information, see the less homepage at 1526 http://www.greenwoodsoftware.com/less. 1527 1528 1529 1530 Version 418: 02 Jan 2008 LESS(1) 1531