less.man revision 240121
1160040SmarcelLESS(1) LESS(1) 2160040Smarcel 3160040Smarcel 4160040Smarcel 5160040Smarcel[1mNAME[0m 6160040Smarcel less - opposite of more 7160040Smarcel 8160040Smarcel[1mSYNOPSIS[0m 9160040Smarcel [1mless -?[0m 10160040Smarcel [1mless --help[0m 11160040Smarcel [1mless -V[0m 12160040Smarcel [1mless --version[0m 13160040Smarcel [1mless [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~][0m 14160040Smarcel [1m[-b [4m[22mspace[24m[1m] [-h [4m[22mlines[24m[1m] [-j [4m[22mline[24m[1m] [-k [4m[22mkeyfile[24m[1m][0m 15160040Smarcel [1m[-{oO} [4m[22mlogfile[24m[1m] [-p [4m[22mpattern[24m[1m] [-P [4m[22mprompt[24m[1m] [-t [4m[22mtag[24m[1m][0m 16160040Smarcel [1m[-T [4m[22mtagsfile[24m[1m] [-x [4m[22mtab[24m[1m,...] [-y [4m[22mlines[24m[1m] [-[z] [4m[22mlines[24m[1m][0m 17160040Smarcel [1m[-# [4m[22mshift[24m[1m] [+[+][4m[22mcmd[24m[1m] [--] [[4m[22mfilename[24m[1m]...[0m 18160040Smarcel (See the OPTIONS section for alternate option syntax with long option 19160040Smarcel names.) 20160040Smarcel 21160040Smarcel 22160040Smarcel[1mDESCRIPTION[0m 23160040Smarcel [4mLess[24m is a program similar to [4mmore[24m (1), but which allows backward move- 24160040Smarcel ment in the file as well as forward movement. Also, [4mless[24m does not have 25160040Smarcel to read the entire input file before starting, so with large input 26160040Smarcel files it starts up faster than text editors like [4mvi[24m (1). [4mLess[24m uses 27160040Smarcel termcap (or terminfo on some systems), so it can run on a variety of 28160040Smarcel terminals. There is even limited support for hardcopy terminals. (On 29160040Smarcel a hardcopy terminal, lines which should be printed at the top of the 30160040Smarcel screen are prefixed with a caret.) 31160040Smarcel 32160040Smarcel Commands are based on both [4mmore[24m and [4mvi.[24m Commands may be preceded by a 33160040Smarcel decimal number, called N in the descriptions below. The number is used 34160040Smarcel by some commands, as indicated. 35160040Smarcel 36160040Smarcel 37160040Smarcel[1mCOMMANDS[0m 38160040Smarcel In the following descriptions, ^X means control-X. ESC stands for the 39160040Smarcel ESCAPE key; for example ESC-v means the two character sequence 40160040Smarcel "ESCAPE", then "v". 41160040Smarcel 42160040Smarcel h or H Help: display a summary of these commands. If you forget all 43160040Smarcel the other commands, remember this one. 44160040Smarcel 45160040Smarcel SPACE or ^V or f or ^F 46160040Smarcel Scroll forward N lines, default one window (see option -z 47160040Smarcel below). If N is more than the screen size, only the final 48160040Smarcel screenful is displayed. Warning: some systems use ^V as a spe- 49160040Smarcel cial literalization character. 50160040Smarcel 51160040Smarcel z Like SPACE, but if N is specified, it becomes the new window 52160040Smarcel size. 53160040Smarcel 54160040Smarcel ESC-SPACE 55160040Smarcel Like SPACE, but scrolls a full screenful, even if it reaches 56160040Smarcel end-of-file in the process. 57160040Smarcel 58160040Smarcel ENTER or RETURN or ^N or e or ^E or j or ^J 59160040Smarcel Scroll forward N lines, default 1. The entire N lines are dis- 60160040Smarcel played, even if N is more than the screen size. 61160040Smarcel 62160040Smarcel d or ^D 63160040Smarcel Scroll forward N lines, default one half of the screen size. If 64160040Smarcel N is specified, it becomes the new default for subsequent d and 65160040Smarcel u commands. 66160040Smarcel 67160040Smarcel b or ^B or ESC-v 68160040Smarcel Scroll backward N lines, default one window (see option -z 69160040Smarcel below). If N is more than the screen size, only the final 70160040Smarcel screenful is displayed. 71160040Smarcel 72160040Smarcel w Like ESC-v, but if N is specified, it becomes the new window 73160040Smarcel size. 74160040Smarcel 75160040Smarcel y or ^Y or ^P or k or ^K 76160040Smarcel Scroll backward N lines, default 1. The entire N lines are dis- 77160040Smarcel played, even if N is more than the screen size. Warning: some 78160040Smarcel systems use ^Y as a special job control character. 79160040Smarcel 80160040Smarcel u or ^U 81160040Smarcel Scroll backward N lines, default one half of the screen size. 82160040Smarcel If N is specified, it becomes the new default for subsequent d 83160040Smarcel and u commands. 84160040Smarcel 85160040Smarcel ESC-) or RIGHTARROW 86160040Smarcel Scroll horizontally right N characters, default half the screen 87160040Smarcel width (see the -# option). If a number N is specified, it 88160040Smarcel becomes the default for future RIGHTARROW and LEFTARROW com- 89160040Smarcel 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 ESC-F Like F, but as soon as a line is found which matches the last 111 search pattern, the terminal bell is rung and forward scrolling 112 stops. 113 114 g or < or ESC-< 115 Go to line N in the file, default 1 (beginning of file). (Warn- 116 ing: this may be slow if N is large.) 117 118 G or > or ESC-> 119 Go to line N in the file, default the end of the file. (Warn- 120 ing: this may be slow if N is large, or if N is not specified 121 and standard input, rather than a file, is being read.) 122 123 p or % Go to a position N percent into the file. N should be between 0 124 and 100, and may contain a decimal point. 125 126 P Go to the line containing byte offset N in the file. 127 128 { If a left curly bracket appears in the top line displayed on the 129 screen, the { command will go to the matching right curly 130 bracket. The matching right curly bracket is positioned on the 131 bottom line of the screen. If there is more than one left curly 132 bracket on the top line, a number N may be used to specify the 133 N-th bracket on the line. 134 135 } If a right curly bracket appears in the bottom line displayed on 136 the screen, the } command will go to the matching left curly 137 bracket. The matching left curly bracket is positioned on the 138 top line of the screen. If there is more than one right curly 139 bracket on the top line, a number N may be used to specify the 140 N-th bracket on the line. 141 142 ( Like {, but applies to parentheses rather than curly brackets. 143 144 ) Like }, but applies to parentheses rather than curly brackets. 145 146 [ Like {, but applies to square brackets rather than curly brack- 147 ets. 148 149 ] Like }, but applies to square brackets rather than curly brack- 150 ets. 151 152 ESC-^F Followed by two characters, acts like {, but uses the two char- 153 acters as open and close brackets, respectively. For example, 154 "ESC ^F < >" could be used to go forward to the > which matches 155 the < in the top displayed line. 156 157 ESC-^B Followed by two characters, acts like }, but uses the two char- 158 acters as open and close brackets, respectively. For example, 159 "ESC ^B < >" could be used to go backward to the < which matches 160 the > in the bottom displayed line. 161 162 m Followed by any lowercase letter, marks the current position 163 with that letter. 164 165 ' (Single quote.) Followed by any lowercase letter, returns to 166 the position which was previously marked with that letter. Fol- 167 lowed by another single quote, returns to the position at which 168 the last "large" movement command was executed. Followed by a ^ 169 or $, jumps to the beginning or end of the file respectively. 170 Marks are preserved when a new file is examined, so the ' com- 171 mand can be used to switch between input files. 172 173 ^X^X Same as single quote. 174 175 /pattern 176 Search forward in the file for the N-th line containing the pat- 177 tern. N defaults to 1. The pattern is a regular expression, as 178 recognized by the regular expression library supplied by your 179 system. The search starts at the first line displayed (but see 180 the -a and -j options, which change this). 181 182 Certain characters are special if entered at the beginning of 183 the pattern; they modify the type of search rather than become 184 part of the pattern: 185 186 ^N or ! 187 Search for lines which do NOT match the pattern. 188 189 ^E or * 190 Search multiple files. That is, if the search reaches 191 the END of the current file without finding a match, the 192 search continues in the next file in the command line 193 list. 194 195 ^F or @ 196 Begin the search at the first line of the FIRST file in 197 the command line list, regardless of what is currently 198 displayed on the screen or the settings of the -a or -j 199 options. 200 201 ^K Highlight any text which matches the pattern on the cur- 202 rent screen, but don't move to the first match (KEEP cur- 203 rent position). 204 205 ^R Don't interpret regular expression metacharacters; that 206 is, do a simple textual comparison. 207 208 ?pattern 209 Search backward in the file for the N-th line containing the 210 pattern. The search starts at the line immediately before the 211 top line displayed. 212 213 Certain characters are special as in the / command: 214 215 ^N or ! 216 Search for lines which do NOT match the pattern. 217 218 ^E or * 219 Search multiple files. That is, if the search reaches 220 the beginning of the current file without finding a 221 match, the search continues in the previous file in the 222 command line list. 223 224 ^F or @ 225 Begin the search at the last line of the last file in the 226 command line list, regardless of what is currently dis- 227 played on the screen or the settings of the -a or -j 228 options. 229 230 ^K As in forward searches. 231 232 ^R As in forward searches. 233 234 ESC-/pattern 235 Same as "/*". 236 237 ESC-?pattern 238 Same as "?*". 239 240 n Repeat previous search, for N-th line containing the last pat- 241 tern. If the previous search was modified by ^N, the search is 242 made for the N-th line NOT containing the pattern. If the pre- 243 vious search was modified by ^E, the search continues in the 244 next (or previous) file if not satisfied in the current file. 245 If the previous search was modified by ^R, the search is done 246 without using regular expressions. There is no effect if the 247 previous search was modified by ^F or ^K. 248 249 N Repeat previous search, but in the reverse direction. 250 251 ESC-n Repeat previous search, but crossing file boundaries. The 252 effect is as if the previous search were modified by *. 253 254 ESC-N Repeat previous search, but in the reverse direction and cross- 255 ing file boundaries. 256 257 ESC-u Undo search highlighting. Turn off highlighting of strings 258 matching the current search pattern. If highlighting is already 259 off because of a previous ESC-u command, turn highlighting back 260 on. Any search command will also turn highlighting back on. 261 (Highlighting can also be disabled by toggling the -G option; in 262 that case search commands do not turn highlighting back on.) 263 264 &pattern 265 Display only lines which match the pattern; lines which do not 266 match the pattern are not displayed. If pattern is empty (if 267 you type & immediately followed by ENTER), any filtering is 268 turned off, and all lines are displayed. While filtering is in 269 effect, an ampersand is displayed at the beginning of the 270 prompt, as a reminder that some lines in the file may be hidden. 271 272 Certain characters are special as in the / command: 273 274 ^N or ! 275 Display only lines which do NOT match the pattern. 276 277 ^R Don't interpret regular expression metacharacters; that 278 is, do a simple textual comparison. 279 280 :e [filename] 281 Examine a new file. If the filename is missing, the "current" 282 file (see the :n and :p commands below) from the list of files 283 in the command line is re-examined. A percent sign (%) in the 284 filename is replaced by the name of the current file. A pound 285 sign (#) is replaced by the name of the previously examined 286 file. However, two consecutive percent signs are simply 287 replaced with a single percent sign. This allows you to enter a 288 filename that contains a percent sign in the name. Similarly, 289 two consecutive pound signs are replaced with a single pound 290 sign. The filename is inserted into the command line list of 291 files so that it can be seen by subsequent :n and :p commands. 292 If the filename consists of several files, they are all inserted 293 into the list of files and the first one is examined. If the 294 filename contains one or more spaces, the entire filename should 295 be enclosed in double quotes (also see the -" option). 296 297 ^X^V or E 298 Same as :e. Warning: some systems use ^V as a special literal- 299 ization character. On such systems, you may not be able to use 300 ^V. 301 302 :n Examine the next file (from the list of files given in the com- 303 mand line). If a number N is specified, the N-th next file is 304 examined. 305 306 :p Examine the previous file in the command line list. If a number 307 N is specified, the N-th previous file is examined. 308 309 :x Examine the first file in the command line list. If a number N 310 is specified, the N-th file in the list is examined. 311 312 :d Remove the current file from the list of files. 313 314 t Go to the next tag, if there were more than one matches for the 315 current tag. See the -t option for more details about tags. 316 317 T Go to the previous tag, if there were more than one matches for 318 the current tag. 319 320 = or ^G or :f 321 Prints some information about the file being viewed, including 322 its name and the line number and byte offset of the bottom line 323 being displayed. If possible, it also prints the length of the 324 file, the number of lines in the file and the percent of the 325 file above the last displayed line. 326 327 - Followed by one of the command line option letters (see OPTIONS 328 below), this will change the setting of that option and print a 329 message describing the new setting. If a ^P (CONTROL-P) is 330 entered immediately after the dash, the setting of the option is 331 changed but no message is printed. If the option letter has a 332 numeric value (such as -b or -h), or a string value (such as -P 333 or -t), a new value may be entered after the option letter. If 334 no new value is entered, a message describing the current set- 335 ting is printed and nothing is changed. 336 337 -- Like the - command, but takes a long option name (see OPTIONS 338 below) rather than a single option letter. You must press ENTER 339 or RETURN after typing the option name. A ^P immediately after 340 the second dash suppresses printing of a message describing the 341 new setting, as in the - command. 342 343 -+ Followed by one of the command line option letters this will 344 reset the option to its default setting and print a message 345 describing the new setting. (The "-+[4mX[24m" command does the same 346 thing as "-+[4mX[24m" on the command line.) This does not work for 347 string-valued options. 348 349 --+ Like the -+ command, but takes a long option name rather than a 350 single option letter. 351 352 -! Followed by one of the command line option letters, this will 353 reset the option to the "opposite" of its default setting and 354 print a message describing the new setting. This does not work 355 for numeric or string-valued options. 356 357 --! Like the -! command, but takes a long option name rather than a 358 single option letter. 359 360 _ (Underscore.) Followed by one of the command line option let- 361 ters, this will print a message describing the current setting 362 of that option. The setting of the option is not changed. 363 364 __ (Double underscore.) Like the _ (underscore) command, but takes 365 a long option name rather than a single option letter. You must 366 press ENTER or RETURN after typing the option name. 367 368 +cmd Causes the specified cmd to be executed each time a new file is 369 examined. For example, +G causes [4mless[24m to initially display each 370 file starting at the end rather than the beginning. 371 372 V Prints the version number of [4mless[24m being run. 373 374 q or Q or :q or :Q or ZZ 375 Exits [4mless.[0m 376 377 The following four commands may or may not be valid, depending on your 378 particular installation. 379 380 v Invokes an editor to edit the current file being viewed. The 381 editor is taken from the environment variable VISUAL if defined, 382 or EDITOR if VISUAL is not defined, or defaults to "vi" if nei- 383 ther VISUAL nor EDITOR is defined. See also the discussion of 384 LESSEDIT under the section on PROMPTS below. 385 386 ! shell-command 387 Invokes a shell to run the shell-command given. A percent sign 388 (%) in the command is replaced by the name of the current file. 389 A pound sign (#) is replaced by the name of the previously exam- 390 ined file. "!!" repeats the last shell command. "!" with no 391 shell command simply invokes a shell. On Unix systems, the 392 shell is taken from the environment variable SHELL, or defaults 393 to "sh". On MS-DOS and OS/2 systems, the shell is the normal 394 command processor. 395 396 | <m> shell-command 397 <m> represents any mark letter. Pipes a section of the input 398 file to the given shell command. The section of the file to be 399 piped is between the first line on the current screen and the 400 position marked by the letter. <m> may also be ^ or $ to indi- 401 cate beginning or end of file respectively. If <m> is . or new- 402 line, the current screen is piped. 403 404 s filename 405 Save the input to a file. This only works if the input is a 406 pipe, not an ordinary file. 407 408[1mOPTIONS[0m 409 Command line options are described below. Most options may be changed 410 while [4mless[24m is running, via the "-" command. 411 412 Most options may be given in one of two forms: either a dash followed 413 by a single letter, or two dashes followed by a long option name. A 414 long option name may be abbreviated as long as the abbreviation is 415 unambiguous. For example, --quit-at-eof may be abbreviated --quit, but 416 not --qui, since both --quit-at-eof and --quiet begin with --qui. Some 417 long option names are in uppercase, such as --QUIT-AT-EOF, as distinct 418 from --quit-at-eof. Such option names need only have their first let- 419 ter capitalized; the remainder of the name may be in either case. For 420 example, --Quit-at-eof is equivalent to --QUIT-AT-EOF. 421 422 Options are also taken from the environment variable "LESS". For exam- 423 ple, to avoid typing "less -options ..." each time [4mless[24m is invoked, you 424 might tell [4mcsh:[0m 425 426 setenv LESS "-options" 427 428 or if you use [4msh:[0m 429 430 LESS="-options"; export LESS 431 432 On MS-DOS, you don't need the quotes, but you should replace any per- 433 cent signs in the options string by double percent signs. 434 435 The environment variable is parsed before the command line, so command 436 line options override the LESS environment variable. If an option 437 appears in the LESS variable, it can be reset to its default value on 438 the command line by beginning the command line option with "-+". 439 440 For options like -P or -D which take a following string, a dollar sign 441 ($) must be used to signal the end of the string. For example, to set 442 two -D options on MS-DOS, you must have a dollar sign between them, 443 like this: 444 445 LESS="-Dn9.1$-Ds4.1" 446 447 448 -? or --help 449 This option displays a summary of the commands accepted by [4mless[0m 450 (the same as the h command). (Depending on how your shell 451 interprets the question mark, it may be necessary to quote the 452 question mark, thus: "-\?".) 453 454 -a or --search-skip-screen 455 By default, forward searches start at the top of the displayed 456 screen and backwards searches start at the bottom of the dis- 457 played screen (except for repeated searches invoked by the n or 458 N commands, which start after or before the "target" line 459 respectively; see the -j option for more about the target line). 460 The -a option causes forward searches to instead start at the 461 bottom of the screen and backward searches to start at the top 462 of the screen, thus skipping all lines displayed on the screen. 463 464 -A or --SEARCH-SKIP-SCREEN 465 Causes all forward searches (not just non-repeated searches) to 466 start just after the target line, and all backward searches to 467 start just before the target line. Thus, forward searches will 468 skip part of the displayed screen (from the first line up to and 469 including the target line). Similarly backwards searches will 470 skip the displayed screen from the last line up to and including 471 the target line. This was the default behavior in less versions 472 prior to 441. 473 474 -b[4mn[24m or --buffers=[4mn[0m 475 Specifies the amount of buffer space [4mless[24m will use for each 476 file, in units of kilobytes (1024 bytes). By default 64K of 477 buffer space is used for each file (unless the file is a pipe; 478 see the -B option). The -b option specifies instead that [4mn[0m 479 kilobytes of buffer space should be used for each file. If [4mn[24m is 480 -1, buffer space is unlimited; that is, the entire file can be 481 read into memory. 482 483 -B or --auto-buffers 484 By default, when data is read from a pipe, buffers are allocated 485 automatically as needed. If a large amount of data is read from 486 the pipe, this can cause a large amount of memory to be allo- 487 cated. The -B option disables this automatic allocation of buf- 488 fers for pipes, so that only 64K (or the amount of space speci- 489 fied by the -b option) is used for the pipe. Warning: use of -B 490 can result in erroneous display, since only the most recently 491 viewed part of the piped data is kept in memory; any earlier 492 data is lost. 493 494 -c or --clear-screen 495 Causes full screen repaints to be painted from the top line 496 down. By default, full screen repaints are done by scrolling 497 from the bottom of the screen. 498 499 -C or --CLEAR-SCREEN 500 Same as -c, for compatibility with older versions of [4mless.[0m 501 502 -d or --dumb 503 The -d option suppresses the error message normally displayed if 504 the terminal is dumb; that is, lacks some important capability, 505 such as the ability to clear the screen or scroll backward. The 506 -d option does not otherwise change the behavior of [4mless[24m on a 507 dumb terminal. 508 509 -D[1mx[4m[22mcolor[24m or --color=[1mx[4m[22mcolor[0m 510 [MS-DOS only] Sets the color of the text displayed. [1mx [22mis a sin- 511 gle character which selects the type of text whose color is 512 being set: n=normal, s=standout, d=bold, u=underlined, k=blink. 513 [4mcolor[24m is a pair of numbers separated by a period. The first 514 number selects the foreground color and the second selects the 515 background color of the text. A single number [4mN[24m is the same as 516 [4mN.M[24m, where [4mM[24m is the normal background color. 517 518 519 -e or --quit-at-eof 520 Causes [4mless[24m to automatically exit the second time it reaches 521 end-of-file. By default, the only way to exit [4mless[24m is via the 522 "q" command. 523 524 -E or --QUIT-AT-EOF 525 Causes [4mless[24m to automatically exit the first time it reaches end- 526 of-file. 527 528 -f or --force 529 Forces non-regular files to be opened. (A non-regular file is a 530 directory or a device special file.) Also suppresses the warn- 531 ing message when a binary file is opened. By default, [4mless[24m will 532 refuse to open non-regular files. Note that some operating sys- 533 tems will not allow directories to be read, even if -f is set. 534 535 -F or --quit-if-one-screen 536 Causes [4mless[24m to automatically exit if the entire file can be dis- 537 played on the first screen. 538 539 -g or --hilite-search 540 Normally, [4mless[24m will highlight ALL strings which match the last 541 search command. The -g option changes this behavior to high- 542 light only the particular string which was found by the last 543 search command. This can cause [4mless[24m to run somewhat faster than 544 the default. 545 546 -G or --HILITE-SEARCH 547 The -G option suppresses all highlighting of strings found by 548 search commands. 549 550 -h[4mn[24m or --max-back-scroll=[4mn[0m 551 Specifies a maximum number of lines to scroll backward. If it 552 is necessary to scroll backward more than [4mn[24m lines, the screen is 553 repainted in a forward direction instead. (If the terminal does 554 not have the ability to scroll backward, -h0 is implied.) 555 556 -i or --ignore-case 557 Causes searches to ignore case; that is, uppercase and lowercase 558 are considered identical. This option is ignored if any upper- 559 case letters appear in the search pattern; in other words, if a 560 pattern contains uppercase letters, then that search does not 561 ignore case. 562 563 -I or --IGNORE-CASE 564 Like -i, but searches ignore case even if the pattern contains 565 uppercase letters. 566 567 -j[4mn[24m or --jump-target=[4mn[0m 568 Specifies a line on the screen where the "target" line is to be 569 positioned. The target line is the line specified by any com- 570 mand to search for a pattern, jump to a line number, jump to a 571 file percentage or jump to a tag. The screen line may be speci- 572 fied by a number: the top line on the screen is 1, the next is 573 2, and so on. The number may be negative to specify a line rel- 574 ative to the bottom of the screen: the bottom line on the screen 575 is -1, the second to the bottom is -2, and so on. Alternately, 576 the screen line may be specified as a fraction of the height of 577 the screen, starting with a decimal point: .5 is in the middle 578 of the screen, .3 is three tenths down from the first line, and 579 so on. If the line is specified as a fraction, the actual line 580 number is recalculated if the terminal window is resized, so 581 that the target line remains at the specified fraction of the 582 screen height. If any form of the -j option is used, forward 583 searches begin at the line immediately after the target line, 584 and backward searches begin at the target line, unless changed 585 by -a or -A. For example, if "-j4" is used, the target line is 586 the fourth line on the screen, so forward searches begin at the 587 fifth line on the screen. 588 589 -J or --status-column 590 Displays a status column at the left edge of the screen. The 591 status column shows the lines that matched the current search. 592 The status column is also used if the -w or -W option is in 593 effect. 594 595 -k[4mfilename[24m or --lesskey-file=[4mfilename[0m 596 Causes [4mless[24m to open and interpret the named file as a [4mlesskey[0m 597 (1) file. Multiple -k options may be specified. If the LESSKEY 598 or LESSKEY_SYSTEM environment variable is set, or if a lesskey 599 file is found in a standard place (see KEY BINDINGS), it is also 600 used as a [4mlesskey[24m file. 601 602 -K or --quit-on-intr 603 Causes [4mless[24m to exit immediately (with status 2) when an inter- 604 rupt character (usually ^C) is typed. Normally, an interrupt 605 character causes [4mless[24m to stop whatever it is doing and return to 606 its command prompt. Note that use of this option makes it 607 impossible to return to the command prompt from the "F" command. 608 609 -L or --no-lessopen 610 Ignore the LESSOPEN environment variable (see the INPUT PRE- 611 PROCESSOR section below). This option can be set from within 612 [4mless[24m, but it will apply only to files opened subsequently, not 613 to the file which is currently open. 614 615 -m or --long-prompt 616 Causes [4mless[24m to prompt verbosely (like [4mmore[24m), with the percent 617 into the file. By default, [4mless[24m prompts with a colon. 618 619 -M or --LONG-PROMPT 620 Causes [4mless[24m to prompt even more verbosely than [4mmore.[0m 621 622 -n or --line-numbers 623 Suppresses line numbers. The default (to use line numbers) may 624 cause [4mless[24m to run more slowly in some cases, especially with a 625 very large input file. Suppressing line numbers with the -n 626 option will avoid this problem. Using line numbers means: the 627 line number will be displayed in the verbose prompt and in the = 628 command, and the v command will pass the current line number to 629 the editor (see also the discussion of LESSEDIT in PROMPTS 630 below). 631 632 -N or --LINE-NUMBERS 633 Causes a line number to be displayed at the beginning of each 634 line in the display. 635 636 -o[4mfilename[24m or --log-file=[4mfilename[0m 637 Causes [4mless[24m to copy its input to the named file as it is being 638 viewed. This applies only when the input file is a pipe, not an 639 ordinary file. If the file already exists, [4mless[24m will ask for 640 confirmation before overwriting it. 641 642 -O[4mfilename[24m or --LOG-FILE=[4mfilename[0m 643 The -O option is like -o, but it will overwrite an existing file 644 without asking for confirmation. 645 646 If no log file has been specified, the -o and -O options can be 647 used from within [4mless[24m to specify a log file. Without a file 648 name, they will simply report the name of the log file. The "s" 649 command is equivalent to specifying -o from within [4mless.[0m 650 651 -p[4mpattern[24m or --pattern=[4mpattern[0m 652 The -p option on the command line is equivalent to specifying 653 +/[4mpattern[24m; that is, it tells [4mless[24m to start at the first occur- 654 rence of [4mpattern[24m in the file. 655 656 -P[4mprompt[24m or --prompt=[4mprompt[0m 657 Provides a way to tailor the three prompt styles to your own 658 preference. This option would normally be put in the LESS envi- 659 ronment variable, rather than being typed in with each [4mless[24m com- 660 mand. Such an option must either be the last option in the LESS 661 variable, or be terminated by a dollar sign. -Ps followed by a 662 string changes the default (short) prompt to that string. -Pm 663 changes the medium (-m) prompt. -PM changes the long (-M) 664 prompt. -Ph changes the prompt for the help screen. -P= 665 changes the message printed by the = command. -Pw changes the 666 message printed while waiting for data (in the F command). All 667 prompt strings consist of a sequence of letters and special 668 escape sequences. See the section on PROMPTS for more details. 669 670 -q or --quiet or --silent 671 Causes moderately "quiet" operation: the terminal bell is not 672 rung if an attempt is made to scroll past the end of the file or 673 before the beginning of the file. If the terminal has a "visual 674 bell", it is used instead. The bell will be rung on certain 675 other errors, such as typing an invalid character. The default 676 is to ring the terminal bell in all such cases. 677 678 -Q or --QUIET or --SILENT 679 Causes totally "quiet" operation: the terminal bell is never 680 rung. 681 682 -r or --raw-control-chars 683 Causes "raw" control characters to be displayed. The default is 684 to display control characters using the caret notation; for 685 example, a control-A (octal 001) is displayed as "^A". Warning: 686 when the -r option is used, [4mless[24m cannot keep track of the actual 687 appearance of the screen (since this depends on how the screen 688 responds to each type of control character). Thus, various dis- 689 play problems may result, such as long lines being split in the 690 wrong place. 691 692 -R or --RAW-CONTROL-CHARS 693 Like -r, but only ANSI "color" escape sequences are output in 694 "raw" form. Unlike -r, the screen appearance is maintained cor- 695 rectly in most cases. ANSI "color" escape sequences are 696 sequences of the form: 697 698 ESC [ ... m 699 700 where the "..." is zero or more color specification characters 701 For the purpose of keeping track of screen appearance, ANSI 702 color escape sequences are assumed to not move the cursor. You 703 can make [4mless[24m think that characters other than "m" can end ANSI 704 color escape sequences by setting the environment variable 705 LESSANSIENDCHARS to the list of characters which can end a color 706 escape sequence. And you can make [4mless[24m think that characters 707 other than the standard ones may appear between the ESC and the 708 m by setting the environment variable LESSANSIMIDCHARS to the 709 list of characters which can appear. 710 711 -s or --squeeze-blank-lines 712 Causes consecutive blank lines to be squeezed into a single 713 blank line. This is useful when viewing [4mnroff[24m output. 714 715 -S or --chop-long-lines 716 Causes lines longer than the screen width to be chopped (trun- 717 cated) rather than wrapped. That is, the portion of a long line 718 that does not fit in the screen width is not shown. The default 719 is to wrap long lines; that is, display the remainder on the 720 next line. 721 722 -t[4mtag[24m or --tag=[4mtag[0m 723 The -t option, followed immediately by a TAG, will edit the file 724 containing that tag. For this to work, tag information must be 725 available; for example, there may be a file in the current 726 directory called "tags", which was previously built by [4mctags[24m (1) 727 or an equivalent command. If the environment variable LESSGLOB- 728 ALTAGS is set, it is taken to be the name of a command compati- 729 ble with [4mglobal[24m (1), and that command is executed to find the 730 tag. (See http://www.gnu.org/software/global/global.html). The 731 -t option may also be specified from within [4mless[24m (using the - 732 command) as a way of examining a new file. The command ":t" is 733 equivalent to specifying -t from within [4mless.[0m 734 735 -T[4mtagsfile[24m or --tag-file=[4mtagsfile[0m 736 Specifies a tags file to be used instead of "tags". 737 738 -u or --underline-special 739 Causes backspaces and carriage returns to be treated as print- 740 able characters; that is, they are sent to the terminal when 741 they appear in the input. 742 743 -U or --UNDERLINE-SPECIAL 744 Causes backspaces, tabs and carriage returns to be treated as 745 control characters; that is, they are handled as specified by 746 the -r option. 747 748 By default, if neither -u nor -U is given, backspaces which 749 appear adjacent to an underscore character are treated spe- 750 cially: the underlined text is displayed using the terminal's 751 hardware underlining capability. Also, backspaces which appear 752 between two identical characters are treated specially: the 753 overstruck text is printed using the terminal's hardware bold- 754 face capability. Other backspaces are deleted, along with the 755 preceding character. Carriage returns immediately followed by a 756 newline are deleted. Other carriage returns are handled as 757 specified by the -r option. Text which is overstruck or under- 758 lined can be searched for if neither -u nor -U is in effect. 759 760 -V or --version 761 Displays the version number of [4mless.[0m 762 763 -w or --hilite-unread 764 Temporarily highlights the first "new" line after a forward 765 movement of a full page. The first "new" line is the line imme- 766 diately following the line previously at the bottom of the 767 screen. Also highlights the target line after a g or p command. 768 The highlight is removed at the next command which causes move- 769 ment. The entire line is highlighted, unless the -J option is 770 in effect, in which case only the status column is highlighted. 771 772 -W or --HILITE-UNREAD 773 Like -w, but temporarily highlights the first new line after any 774 forward movement command larger than one line. 775 776 -x[4mn[24m,... or --tabs=[4mn[24m,... 777 Sets tab stops. If only one [4mn[24m is specified, tab stops are set 778 at multiples of [4mn[24m. If multiple values separated by commas are 779 specified, tab stops are set at those positions, and then con- 780 tinue with the same spacing as the last two. For example, 781 [4m-x9,17[24m will set tabs at positions 9, 17, 25, 33, etc. The 782 default for [4mn[24m is 8. 783 784 -X or --no-init 785 Disables sending the termcap initialization and deinitialization 786 strings to the terminal. This is sometimes desirable if the 787 deinitialization string does something unnecessary, like clear- 788 ing the screen. 789 790 -y[4mn[24m or --max-forw-scroll=[4mn[0m 791 Specifies a maximum number of lines to scroll forward. If it is 792 necessary to scroll forward more than [4mn[24m lines, the screen is 793 repainted instead. The -c or -C option may be used to repaint 794 from the top of the screen if desired. By default, any forward 795 movement causes scrolling. 796 797 -[z][4mn[24m or --window=[4mn[0m 798 Changes the default scrolling window size to [4mn[24m lines. The 799 default is one screenful. The z and w commands can also be used 800 to change the window size. The "z" may be omitted for compati- 801 bility with some versions of [4mmore.[24m If the number [4mn[24m is negative, 802 it indicates [4mn[24m lines less than the current screen size. For 803 example, if the screen is 24 lines, [4m-z-4[24m sets the scrolling win- 804 dow to 20 lines. If the screen is resized to 40 lines, the 805 scrolling window automatically changes to 36 lines. 806 807 -[4m"cc[24m or --quotes=[4mcc[0m 808 Changes the filename quoting character. This may be necessary 809 if you are trying to name a file which contains both spaces and 810 quote characters. Followed by a single character, this changes 811 the quote character to that character. Filenames containing a 812 space should then be surrounded by that character rather than by 813 double quotes. Followed by two characters, changes the open 814 quote to the first character, and the close quote to the second 815 character. Filenames containing a space should then be preceded 816 by the open quote character and followed by the close quote 817 character. Note that even after the quote characters are 818 changed, this option remains -" (a dash followed by a double 819 quote). 820 821 -~ or --tilde 822 Normally lines after end of file are displayed as a single tilde 823 (~). This option causes lines after end of file to be displayed 824 as blank lines. 825 826 -# or --shift 827 Specifies the default number of positions to scroll horizontally 828 in the RIGHTARROW and LEFTARROW commands. If the number speci- 829 fied is zero, it sets the default number of positions to one 830 half of the screen width. Alternately, the number may be speci- 831 fied as a fraction of the width of the screen, starting with a 832 decimal point: .5 is half of the screen width, .3 is three 833 tenths of the screen width, and so on. If the number is speci- 834 fied as a fraction, the actual number of scroll positions is 835 recalculated if the terminal window is resized, so that the 836 actual scroll remains at the specified fraction of the screen 837 width. 838 839 --no-keypad 840 Disables sending the keypad initialization and deinitialization 841 strings to the terminal. This is sometimes useful if the keypad 842 strings make the numeric keypad behave in an undesirable manner. 843 844 --follow-name 845 Normally, if the input file is renamed while an F command is 846 executing, [4mless[24m will continue to display the contents of the 847 original file despite its name change. If --follow-name is 848 specified, during an F command [4mless[24m will periodically attempt to 849 reopen the file by name. If the reopen succeeds and the file is 850 a different file from the original (which means that a new file 851 has been created with the same name as the original (now 852 renamed) file), [4mless[24m will display the contents of that new file. 853 854 -- A command line argument of "--" marks the end of option argu- 855 ments. Any arguments following this are interpreted as file- 856 names. This can be useful when viewing a file whose name begins 857 with a "-" or "+". 858 859 + If a command line option begins with [1m+[22m, the remainder of that 860 option is taken to be an initial command to [4mless.[24m For example, 861 +G tells [4mless[24m to start at the end of the file rather than the 862 beginning, and +/xyz tells it to start at the first occurrence 863 of "xyz" in the file. As a special case, +<number> acts like 864 +<number>g; that is, it starts the display at the specified line 865 number (however, see the caveat under the "g" command above). 866 If the option starts with ++, the initial command applies to 867 every file being viewed, not just the first one. The + command 868 described previously may also be used to set (or change) an ini- 869 tial command for every file. 870 871 872[1mLINE EDITING[0m 873 When entering command line at the bottom of the screen (for example, a 874 filename for the :e command, or the pattern for a search command), cer- 875 tain keys can be used to manipulate the command line. Most commands 876 have an alternate form in [ brackets ] which can be used if a key does 877 not exist on a particular keyboard. (Note that the forms beginning 878 with ESC do not work in some MS-DOS and Windows systems because ESC is 879 the line erase character.) Any of these special keys may be entered 880 literally by preceding it with the "literal" character, either ^V or 881 ^A. A backslash itself may also be entered literally by entering two 882 backslashes. 883 884 LEFTARROW [ ESC-h ] 885 Move the cursor one space to the left. 886 887 RIGHTARROW [ ESC-l ] 888 Move the cursor one space to the right. 889 890 ^LEFTARROW [ ESC-b or ESC-LEFTARROW ] 891 (That is, CONTROL and LEFTARROW simultaneously.) Move the cur- 892 sor one word to the left. 893 894 ^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ] 895 (That is, CONTROL and RIGHTARROW simultaneously.) Move the cur- 896 sor one word to the right. 897 898 HOME [ ESC-0 ] 899 Move the cursor to the beginning of the line. 900 901 END [ ESC-$ ] 902 Move the cursor to the end of the line. 903 904 BACKSPACE 905 Delete the character to the left of the cursor, or cancel the 906 command if the command line is empty. 907 908 DELETE or [ ESC-x ] 909 Delete the character under the cursor. 910 911 ^BACKSPACE [ ESC-BACKSPACE ] 912 (That is, CONTROL and BACKSPACE simultaneously.) Delete the 913 word to the left of the cursor. 914 915 ^DELETE [ ESC-X or ESC-DELETE ] 916 (That is, CONTROL and DELETE simultaneously.) Delete the word 917 under the cursor. 918 919 UPARROW [ ESC-k ] 920 Retrieve the previous command line. If you first enter some 921 text and then press UPARROW, it will retrieve the previous com- 922 mand which begins with that text. 923 924 DOWNARROW [ ESC-j ] 925 Retrieve the next command line. If you first enter some text 926 and then press DOWNARROW, it will retrieve the next command 927 which begins with that text. 928 929 TAB Complete the partial filename to the left of the cursor. If it 930 matches more than one filename, the first match is entered into 931 the command line. Repeated TABs will cycle thru the other 932 matching filenames. If the completed filename is a directory, a 933 "/" is appended to the filename. (On MS-DOS systems, a "\" is 934 appended.) The environment variable LESSSEPARATOR can be used 935 to specify a different character to append to a directory name. 936 937 BACKTAB [ ESC-TAB ] 938 Like, TAB, but cycles in the reverse direction thru the matching 939 filenames. 940 941 ^L Complete the partial filename to the left of the cursor. If it 942 matches more than one filename, all matches are entered into the 943 command line (if they fit). 944 945 ^U (Unix and OS/2) or ESC (MS-DOS) 946 Delete the entire command line, or cancel the command if the 947 command line is empty. If you have changed your line-kill char- 948 acter in Unix to something other than ^U, that character is used 949 instead of ^U. 950 951 ^G Delete the entire command line and return to the main prompt. 952 953 954[1mKEY BINDINGS[0m 955 You may define your own [4mless[24m commands by using the program [4mlesskey[24m (1) 956 to create a lesskey file. This file specifies a set of command keys 957 and an action associated with each key. You may also use [4mlesskey[24m to 958 change the line-editing keys (see LINE EDITING), and to set environment 959 variables. If the environment variable LESSKEY is set, [4mless[24m uses that 960 as the name of the lesskey file. Otherwise, [4mless[24m looks in a standard 961 place for the lesskey file: On Unix systems, [4mless[24m looks for a lesskey 962 file called "$HOME/.less". On MS-DOS and Windows systems, [4mless[24m looks 963 for a lesskey file called "$HOME/_less", and if it is not found there, 964 then looks for a lesskey file called "_less" in any directory specified 965 in the PATH environment variable. On OS/2 systems, [4mless[24m looks for a 966 lesskey file called "$HOME/less.ini", and if it is not found, then 967 looks for a lesskey file called "less.ini" in any directory specified 968 in the INIT environment variable, and if it not found there, then looks 969 for a lesskey file called "less.ini" in any directory specified in the 970 PATH environment variable. See the [4mlesskey[24m manual page for more 971 details. 972 973 A system-wide lesskey file may also be set up to provide key bindings. 974 If a key is defined in both a local lesskey file and in the system-wide 975 file, key bindings in the local file take precedence over those in the 976 system-wide file. If the environment variable LESSKEY_SYSTEM is set, 977 [4mless[24m uses that as the name of the system-wide lesskey file. Otherwise, 978 [4mless[24m looks in a standard place for the system-wide lesskey file: On 979 Unix systems, the system-wide lesskey file is /usr/local/etc/sysless. 980 (However, if [4mless[24m was built with a different sysconf directory than 981 /usr/local/etc, that directory is where the sysless file is found.) On 982 MS-DOS and Windows systems, the system-wide lesskey file is c:\_sys- 983 less. On OS/2 systems, the system-wide lesskey file is c:\sysless.ini. 984 985 986[1mINPUT PREPROCESSOR[0m 987 You may define an "input preprocessor" for [4mless.[24m Before [4mless[24m opens a 988 file, it first gives your input preprocessor a chance to modify the way 989 the contents of the file are displayed. An input preprocessor is sim- 990 ply an executable program (or shell script), which writes the contents 991 of the file to a different file, called the replacement file. The con- 992 tents of the replacement file are then displayed in place of the con- 993 tents of the original file. However, it will appear to the user as if 994 the original file is opened; that is, [4mless[24m will display the original 995 filename as the name of the current file. 996 997 An input preprocessor receives one command line argument, the original 998 filename, as entered by the user. It should create the replacement 999 file, and when finished, print the name of the replacement file to its 1000 standard output. If the input preprocessor does not output a replace- 1001 ment filename, [4mless[24m uses the original file, as normal. The input pre- 1002 processor is not called when viewing standard input. To set up an 1003 input preprocessor, set the LESSOPEN environment variable to a command 1004 line which will invoke your input preprocessor. This command line 1005 should include one occurrence of the string "%s", which will be 1006 replaced by the filename when the input preprocessor command is 1007 invoked. 1008 1009 When [4mless[24m closes a file opened in such a way, it will call another pro- 1010 gram, called the input postprocessor, which may perform any desired 1011 clean-up action (such as deleting the replacement file created by 1012 LESSOPEN). This program receives two command line arguments, the orig- 1013 inal filename as entered by the user, and the name of the replacement 1014 file. To set up an input postprocessor, set the LESSCLOSE environment 1015 variable to a command line which will invoke your input postprocessor. 1016 It may include two occurrences of the string "%s"; the first is 1017 replaced with the original name of the file and the second with the 1018 name of the replacement file, which was output by LESSOPEN. 1019 1020 For example, on many Unix systems, these two scripts will allow you to 1021 keep files in compressed format, but still let [4mless[24m view them directly: 1022 1023 lessopen.sh: 1024 #! /bin/sh 1025 case "$1" in 1026 *.Z) uncompress - 1027 if [ -s /tmp/less.$$ ]; then 1028 echo /tmp/less.$$ 1029 else 1030 rm -f /tmp/less.$$ 1031 fi 1032 ;; 1033 esac 1034 1035 lessclose.sh: 1036 #! /bin/sh 1037 rm $2 1038 1039 To use these scripts, put them both where they can be executed and set 1040 LESSOPEN="lessopen.sh %s", and LESSCLOSE="lessclose.sh %s %s". More 1041 complex LESSOPEN and LESSCLOSE scripts may be written to accept other 1042 types of compressed files, and so on. 1043 1044 It is also possible to set up an input preprocessor to pipe the file 1045 data directly to [4mless,[24m rather than putting the data into a replacement 1046 file. This avoids the need to decompress the entire file before start- 1047 ing to view it. An input preprocessor that works this way is called an 1048 input pipe. An input pipe, instead of writing the name of a replace- 1049 ment file on its standard output, writes the entire contents of the 1050 replacement file on its standard output. If the input pipe does not 1051 write any characters on its standard output, then there is no replace- 1052 ment file and [4mless[24m uses the original file, as normal. To use an input 1053 pipe, make the first character in the LESSOPEN environment variable a 1054 vertical bar (|) to signify that the input preprocessor is an input 1055 pipe. 1056 1057 For example, on many Unix systems, this script will work like the pre- 1058 vious example scripts: 1059 1060 lesspipe.sh: 1061 #! /bin/sh 1062 case "$1" in 1063 *.Z) uncompress -c $1 2>/dev/null 1064 *) exit 1 1065 ;; 1066 esac 1067 exit $? 1068 1069 To use this script, put it where it can be executed and set 1070 LESSOPEN="|lesspipe.sh %s". 1071 1072 Note that a preprocessor cannot output an empty file, since that is 1073 interpreted as meaning there is no replacement, and the original file 1074 is used. To avoid this, if LESSOPEN starts with two vertical bars, the 1075 exit status of the script becomes meaningful. If the exit status is 1076 zero, the output is considered to be replacement text, even if it 1077 empty. If the exit status is nonzero, any output is ignored and the 1078 original file is used. For compatibility with previous versions of 1079 [4mless,[24m if LESSOPEN starts with only one vertical bar, the exit status of 1080 the preprocessor is ignored. 1081 1082 When an input pipe is used, a LESSCLOSE postprocessor can be used, but 1083 it is usually not necessary since there is no replacement file to clean 1084 up. In this case, the replacement file name passed to the LESSCLOSE 1085 postprocessor is "-". 1086 1087 For compatibility with previous versions of [4mless,[24m the input preproces- 1088 sor or pipe is not used if [4mless[24m is viewing standard input. However, if 1089 the first character of LESSOPEN is a dash (-), the input preprocessor 1090 is used on standard input as well as other files. In this case, the 1091 dash is not considered to be part of the preprocessor command. If 1092 standard input is being viewed, the input preprocessor is passed a file 1093 name consisting of a single dash. Similarly, if the first two charac- 1094 ters of LESSOPEN are vertical bar and dash (|-) or two vertical bars 1095 and a dash (||-), the input pipe is used on standard input as well as 1096 other files. Again, in this case the dash is not considered to be part 1097 of the input pipe command. 1098 1099 1100[1mNATIONAL CHARACTER SETS[0m 1101 There are three types of characters in the input file: 1102 1103 normal characters 1104 can be displayed directly to the screen. 1105 1106 control characters 1107 should not be displayed directly, but are expected to be found 1108 in ordinary text files (such as backspace and tab). 1109 1110 binary characters 1111 should not be displayed directly and are not expected to be 1112 found in text files. 1113 1114 A "character set" is simply a description of which characters are to be 1115 considered normal, control, and binary. The LESSCHARSET environment 1116 variable may be used to select a character set. Possible values for 1117 LESSCHARSET are: 1118 1119 ascii BS, TAB, NL, CR, and formfeed are control characters, all chars 1120 with values between 32 and 126 are normal, and all others are 1121 binary. 1122 1123 iso8859 1124 Selects an ISO 8859 character set. This is the same as ASCII, 1125 except characters between 160 and 255 are treated as normal 1126 characters. 1127 1128 latin1 Same as iso8859. 1129 1130 latin9 Same as iso8859. 1131 1132 dos Selects a character set appropriate for MS-DOS. 1133 1134 ebcdic Selects an EBCDIC character set. 1135 1136 IBM-1047 1137 Selects an EBCDIC character set used by OS/390 Unix Services. 1138 This is the EBCDIC analogue of latin1. You get similar results 1139 by setting either LESSCHARSET=IBM-1047 or LC_CTYPE=en_US in your 1140 environment. 1141 1142 koi8-r Selects a Russian character set. 1143 1144 next Selects a character set appropriate for NeXT computers. 1145 1146 utf-8 Selects the UTF-8 encoding of the ISO 10646 character set. 1147 UTF-8 is special in that it supports multi-byte characters in 1148 the input file. It is the only character set that supports 1149 multi-byte characters. 1150 1151 windows 1152 Selects a character set appropriate for Microsoft Windows (cp 1153 1251). 1154 1155 In rare cases, it may be desired to tailor [4mless[24m to use a character set 1156 other than the ones definable by LESSCHARSET. In this case, the envi- 1157 ronment variable LESSCHARDEF can be used to define a character set. It 1158 should be set to a string where each character in the string represents 1159 one character in the character set. The character "." is used for a 1160 normal character, "c" for control, and "b" for binary. A decimal num- 1161 ber may be used for repetition. For example, "bccc4b." would mean 1162 character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are 1163 binary, and 8 is normal. All characters after the last are taken to be 1164 the same as the last, so characters 9 through 255 would be normal. 1165 (This is an example, and does not necessarily represent any real char- 1166 acter set.) 1167 1168 This table shows the value of LESSCHARDEF which is equivalent to each 1169 of the possible values for LESSCHARSET: 1170 1171 ascii 8bcccbcc18b95.b 1172 dos 8bcccbcc12bc5b95.b. 1173 ebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b 1174 9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b. 1175 IBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc 1176 191.b 1177 iso8859 8bcccbcc18b95.33b. 1178 koi8-r 8bcccbcc18b95.b128. 1179 latin1 8bcccbcc18b95.33b. 1180 next 8bcccbcc18b95.bb125.bb 1181 1182 If neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings 1183 "UTF-8", "UTF8", "utf-8" or "utf8" is found in the LC_ALL, LC_CTYPE or 1184 LANG environment variables, then the default character set is utf-8. 1185 1186 If that string is not found, but your system supports the [4msetlocale[0m 1187 interface, [4mless[24m will use setlocale to determine the character set. 1188 setlocale is controlled by setting the LANG or LC_CTYPE environment 1189 variables. 1190 1191 Finally, if the [4msetlocale[24m interface is also not available, the default 1192 character set is latin1. 1193 1194 Control and binary characters are displayed in standout (reverse 1195 video). Each such character is displayed in caret notation if possible 1196 (e.g. ^A for control-A). Caret notation is used only if inverting the 1197 0100 bit results in a normal printable character. Otherwise, the char- 1198 acter is displayed as a hex number in angle brackets. This format can 1199 be changed by setting the LESSBINFMT environment variable. LESSBINFMT 1200 may begin with a "*" and one character to select the display attribute: 1201 "*k" is blinking, "*d" is bold, "*u" is underlined, "*s" is standout, 1202 and "*n" is normal. If LESSBINFMT does not begin with a "*", normal 1203 attribute is assumed. The remainder of LESSBINFMT is a string which 1204 may include one printf-style escape sequence (a % followed by x, X, o, 1205 d, etc.). For example, if LESSBINFMT is "*u[%x]", binary characters 1206 are displayed in underlined hexadecimal surrounded by brackets. The 1207 default if no LESSBINFMT is specified is "*s<%02X>". Warning: the 1208 result of expanding the character via LESSBINFMT must be less than 31 1209 characters. 1210 1211 When the character set is utf-8, the LESSUTFBINFMT environment variable 1212 acts similarly to LESSBINFMT but it applies to Unicode code points that 1213 were successfully decoded but are unsuitable for display (e.g., unas- 1214 signed code points). Its default value is "<U+%04lX>". Note that 1215 LESSUTFBINFMT and LESSBINFMT share their display attribute setting 1216 ("*x") so specifying one will affect both; LESSUTFBINFMT is read after 1217 LESSBINFMT so its setting, if any, will have priority. Problematic 1218 octets in a UTF-8 file (octets of a truncated sequence, octets of a 1219 complete but non-shortest form sequence, illegal octets, and stray 1220 trailing octets) are displayed individually using LESSBINFMT so as to 1221 facilitate diagnostic of how the UTF-8 file is ill-formed. 1222 1223 1224[1mPROMPTS[0m 1225 The -P option allows you to tailor the prompt to your preference. The 1226 string given to the -P option replaces the specified prompt string. 1227 Certain characters in the string are interpreted specially. The prompt 1228 mechanism is rather complicated to provide flexibility, but the ordi- 1229 nary user need not understand the details of constructing personalized 1230 prompt strings. 1231 1232 A percent sign followed by a single character is expanded according to 1233 what the following character is: 1234 1235 %b[4mX[24m Replaced by the byte offset into the current input file. The b 1236 is followed by a single character (shown as [4mX[24m above) which spec- 1237 ifies the line whose byte offset is to be used. If the charac- 1238 ter is a "t", the byte offset of the top line in the display is 1239 used, an "m" means use the middle line, a "b" means use the bot- 1240 tom line, a "B" means use the line just after the bottom line, 1241 and a "j" means use the "target" line, as specified by the -j 1242 option. 1243 1244 %B Replaced by the size of the current input file. 1245 1246 %c Replaced by the column number of the text appearing in the first 1247 column of the screen. 1248 1249 %d[4mX[24m Replaced by the page number of a line in the input file. The 1250 line to be used is determined by the [4mX[24m, as with the %b option. 1251 1252 %D Replaced by the number of pages in the input file, or equiva- 1253 lently, the page number of the last line in the input file. 1254 1255 %E Replaced by the name of the editor (from the VISUAL environment 1256 variable, or the EDITOR environment variable if VISUAL is not 1257 defined). See the discussion of the LESSEDIT feature below. 1258 1259 %f Replaced by the name of the current input file. 1260 1261 %F Replaced by the last component of the name of the current input 1262 file. 1263 1264 %i Replaced by the index of the current file in the list of input 1265 files. 1266 1267 %l[4mX[24m Replaced by the line number of a line in the input file. The 1268 line to be used is determined by the [4mX[24m, as with the %b option. 1269 1270 %L Replaced by the line number of the last line in the input file. 1271 1272 %m Replaced by the total number of input files. 1273 1274 %p[4mX[24m Replaced by the percent into the current input file, based on 1275 byte offsets. The line used is determined by the [4mX[24m as with the 1276 %b option. 1277 1278 %P[4mX[24m Replaced by the percent into the current input file, based on 1279 line numbers. The line used is determined by the [4mX[24m as with the 1280 %b option. 1281 1282 %s Same as %B. 1283 1284 %t Causes any trailing spaces to be removed. Usually used at the 1285 end of the string, but may appear anywhere. 1286 1287 %x Replaced by the name of the next input file in the list. 1288 1289 If any item is unknown (for example, the file size if input is a pipe), 1290 a question mark is printed instead. 1291 1292 The format of the prompt string can be changed depending on certain 1293 conditions. A question mark followed by a single character acts like 1294 an "IF": depending on the following character, a condition is evalu- 1295 ated. If the condition is true, any characters following the question 1296 mark and condition character, up to a period, are included in the 1297 prompt. If the condition is false, such characters are not included. 1298 A colon appearing between the question mark and the period can be used 1299 to establish an "ELSE": any characters between the colon and the period 1300 are included in the string if and only if the IF condition is false. 1301 Condition characters (which follow a question mark) may be: 1302 1303 ?a True if any characters have been included in the prompt so far. 1304 1305 ?b[4mX[24m True if the byte offset of the specified line is known. 1306 1307 ?B True if the size of current input file is known. 1308 1309 ?c True if the text is horizontally shifted (%c is not zero). 1310 1311 ?d[4mX[24m True if the page number of the specified line is known. 1312 1313 ?e True if at end-of-file. 1314 1315 ?f True if there is an input filename (that is, if input is not a 1316 pipe). 1317 1318 ?l[4mX[24m True if the line number of the specified line is known. 1319 1320 ?L True if the line number of the last line in the file is known. 1321 1322 ?m True if there is more than one input file. 1323 1324 ?n True if this is the first prompt in a new input file. 1325 1326 ?p[4mX[24m True if the percent into the current input file, based on byte 1327 offsets, of the specified line is known. 1328 1329 ?P[4mX[24m True if the percent into the current input file, based on line 1330 numbers, of the specified line is known. 1331 1332 ?s Same as "?B". 1333 1334 ?x True if there is a next input file (that is, if the current 1335 input file is not the last one). 1336 1337 Any characters other than the special ones (question mark, colon, 1338 period, percent, and backslash) become literally part of the prompt. 1339 Any of the special characters may be included in the prompt literally 1340 by preceding it with a backslash. 1341 1342 Some examples: 1343 1344 ?f%f:Standard input. 1345 1346 This prompt prints the filename, if known; otherwise the string "Stan- 1347 dard input". 1348 1349 ?f%f .?ltLine %lt:?pt%pt\%:?btByte %bt:-... 1350 1351 This prompt would print the filename, if known. The filename is fol- 1352 lowed by the line number, if known, otherwise the percent if known, 1353 otherwise the byte offset if known. Otherwise, a dash is printed. 1354 Notice how each question mark has a matching period, and how the % 1355 after the %pt is included literally by escaping it with a backslash. 1356 1357 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x..%t 1358 1359 This prints the filename if this is the first prompt in a file, fol- 1360 lowed by the "file N of N" message if there is more than one input 1361 file. Then, if we are at end-of-file, the string "(END)" is printed 1362 followed by the name of the next file, if there is one. Finally, any 1363 trailing spaces are truncated. This is the default prompt. For refer- 1364 ence, here are the defaults for the other two prompts (-m and -M 1365 respectively). Each is broken into two lines here for readability 1366 only. 1367 1368 ?n?f%f .?m(file %i of %m) ..?e(END) ?x- Next\: %x.: 1369 ?pB%pB\%:byte %bB?s/%s...%t 1370 1371 ?f%f .?n?m(file %i of %m) ..?ltlines %lt-%lb?L/%L. : 1372 byte %bB?s/%s. .?e(END) ?x- Next\: %x.:?pB%pB\%..%t 1373 1374 And here is the default message produced by the = command: 1375 1376 ?f%f .?m(file %i of %m) .?ltlines %lt-%lb?L/%L. . 1377 byte %bB?s/%s. ?e(END) :?pB%pB\%..%t 1378 1379 The prompt expansion features are also used for another purpose: if an 1380 environment variable LESSEDIT is defined, it is used as the command to 1381 be executed when the v command is invoked. The LESSEDIT string is 1382 expanded in the same way as the prompt strings. The default value for 1383 LESSEDIT is: 1384 1385 %E ?lm+%lm. %f 1386 1387 Note that this expands to the editor name, followed by a + and the line 1388 number, followed by the file name. If your editor does not accept the 1389 "+linenumber" syntax, or has other differences in invocation syntax, 1390 the LESSEDIT variable can be changed to modify this default. 1391 1392 1393[1mSECURITY[0m 1394 When the environment variable LESSSECURE is set to 1, [4mless[24m runs in a 1395 "secure" mode. This means these features are disabled: 1396 1397 ! the shell command 1398 1399 | the pipe command 1400 1401 :e the examine command. 1402 1403 v the editing command 1404 1405 s -o log files 1406 1407 -k use of lesskey files 1408 1409 -t use of tags files 1410 1411 metacharacters in filenames, such as * 1412 1413 filename completion (TAB, ^L) 1414 1415 Less can also be compiled to be permanently in "secure" mode. 1416 1417 1418[1mCOMPATIBILITY WITH MORE[0m 1419 If the environment variable LESS_IS_MORE is set to 1, or if the program 1420 is invoked via a file link named "more", [4mless[24m behaves (mostly) in con- 1421 formance with the POSIX "more" command specification. In this mode, 1422 less behaves differently in these ways: 1423 1424 The -e option works differently. If the -e option is not set, [4mless[0m 1425 behaves as if the -E option were set. If the -e option is set, [4mless[0m 1426 behaves as if the -e and -F options were set. 1427 1428 The -m option works differently. If the -m option is not set, the 1429 medium prompt is used, and it is prefixed with the string "--More--". 1430 If the -m option is set, the short prompt is used. 1431 1432 The -n option acts like the -z option. The normal behavior of the -n 1433 option is unavailable in this mode. 1434 1435 The parameter to the -p option is taken to be a [4mless[24m command rather 1436 than a search pattern. 1437 1438 The LESS environment variable is ignored, and the MORE environment 1439 variable is used in its place. 1440 1441 1442[1mENVIRONMENT VARIABLES[0m 1443 Environment variables may be specified either in the system environment 1444 as usual, or in a [4mlesskey[24m (1) file. If environment variables are 1445 defined in more than one place, variables defined in a local lesskey 1446 file take precedence over variables defined in the system environment, 1447 which take precedence over variables defined in the system-wide lesskey 1448 file. 1449 1450 COLUMNS 1451 Sets the number of columns on the screen. Takes precedence over 1452 the number of columns specified by the TERM variable. (But if 1453 you have a windowing system which supports TIOCGWINSZ or 1454 WIOCGETD, the window system's idea of the screen size takes 1455 precedence over the LINES and COLUMNS environment variables.) 1456 1457 EDITOR The name of the editor (used for the v command). 1458 1459 HOME Name of the user's home directory (used to find a lesskey file 1460 on Unix and OS/2 systems). 1461 1462 HOMEDRIVE, HOMEPATH 1463 Concatenation of the HOMEDRIVE and HOMEPATH environment vari- 1464 ables is the name of the user's home directory if the HOME vari- 1465 able is not set (only in the Windows version). 1466 1467 INIT Name of the user's init directory (used to find a lesskey file 1468 on OS/2 systems). 1469 1470 LANG Language for determining the character set. 1471 1472 LC_CTYPE 1473 Language for determining the character set. 1474 1475 LESS Options which are passed to [4mless[24m automatically. 1476 1477 LESSANSIENDCHARS 1478 Characters which may end an ANSI color escape sequence (default 1479 "m"). 1480 1481 LESSANSIMIDCHARS 1482 Characters which may appear between the ESC character and the 1483 end character in an ANSI color escape sequence (default 1484 "0123456789;[?!"'#%()*+ ". 1485 1486 LESSBINFMT 1487 Format for displaying non-printable, non-control characters. 1488 1489 LESSCHARDEF 1490 Defines a character set. 1491 1492 LESSCHARSET 1493 Selects a predefined character set. 1494 1495 LESSCLOSE 1496 Command line to invoke the (optional) input-postprocessor. 1497 1498 LESSECHO 1499 Name of the lessecho program (default "lessecho"). The lessecho 1500 program is needed to expand metacharacters, such as * and ?, in 1501 filenames on Unix systems. 1502 1503 LESSEDIT 1504 Editor prototype string (used for the v command). See discus- 1505 sion under PROMPTS. 1506 1507 LESSGLOBALTAGS 1508 Name of the command used by the -t option to find global tags. 1509 Normally should be set to "global" if your system has the [4mglobal[0m 1510 (1) command. If not set, global tags are not used. 1511 1512 LESSHISTFILE 1513 Name of the history file used to remember search commands and 1514 shell commands between invocations of [4mless.[24m If set to "-" or 1515 "/dev/null", a history file is not used. The default is 1516 "$HOME/.lesshst" on Unix systems, "$HOME/_lesshst" on DOS and 1517 Windows systems, or "$HOME/lesshst.ini" or "$INIT/lesshst.ini" 1518 on OS/2 systems. 1519 1520 LESSHISTSIZE 1521 The maximum number of commands to save in the history file. The 1522 default is 100. 1523 1524 LESSKEY 1525 Name of the default lesskey(1) file. 1526 1527 LESSKEY_SYSTEM 1528 Name of the default system-wide lesskey(1) file. 1529 1530 LESSMETACHARS 1531 List of characters which are considered "metacharacters" by the 1532 shell. 1533 1534 LESSMETAESCAPE 1535 Prefix which less will add before each metacharacter in a com- 1536 mand sent to the shell. If LESSMETAESCAPE is an empty string, 1537 commands containing metacharacters will not be passed to the 1538 shell. 1539 1540 LESSOPEN 1541 Command line to invoke the (optional) input-preprocessor. 1542 1543 LESSSECURE 1544 Runs less in "secure" mode. See discussion under SECURITY. 1545 1546 LESSSEPARATOR 1547 String to be appended to a directory name in filename comple- 1548 tion. 1549 1550 LESSUTFBINFMT 1551 Format for displaying non-printable Unicode code points. 1552 1553 LESS_IS_MORE 1554 Emulate the [4mmore[24m (1) command. 1555 1556 LINES Sets the number of lines on the screen. Takes precedence over 1557 the number of lines specified by the TERM variable. (But if you 1558 have a windowing system which supports TIOCGWINSZ or WIOCGETD, 1559 the window system's idea of the screen size takes precedence 1560 over the LINES and COLUMNS environment variables.) 1561 1562 MORE Options which are passed to [4mless[24m automatically when running in 1563 [4mmore[24m compatible mode. 1564 1565 PATH User's search path (used to find a lesskey file on MS-DOS and 1566 OS/2 systems). 1567 1568 SHELL The shell used to execute the ! command, as well as to expand 1569 filenames. 1570 1571 TERM The type of terminal on which [4mless[24m is being run. 1572 1573 VISUAL The name of the editor (used for the v command). 1574 1575 1576[1mSEE ALSO[0m 1577 lesskey(1) 1578 1579 1580[1mCOPYRIGHT[0m 1581 Copyright (C) 1984-2012 Mark Nudelman 1582 1583 less is part of the GNU project and is free software. You can redis- 1584 tribute it and/or modify it under the terms of either (1) the GNU Gen- 1585 eral Public License as published by the Free Software Foundation; or 1586 (2) the Less License. See the file README in the less distribution for 1587 more details regarding redistribution. You should have received a copy 1588 of the GNU General Public License along with the source for less; see 1589 the file COPYING. If not, write to the Free Software Foundation, 59 1590 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You should also 1591 have received a copy of the Less License; see the file LICENSE. 1592 1593 less is distributed in the hope that it will be useful, but WITHOUT ANY 1594 WARRANTY; without even the implied warranty of MERCHANTABILITY or FIT- 1595 NESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for 1596 more details. 1597 1598 1599[1mAUTHOR[0m 1600 Mark Nudelman <bug-less@gnu.org> 1601 Send bug reports or comments to bug-less@gnu.org. 1602 See http://www.greenwoodsoftware.com/less/bugs.html for the latest list 1603 of known bugs in less. 1604 For more information, see the less homepage at 1605 http://www.greenwoodsoftware.com/less. 1606 1607 1608 1609 Version 451: 21 Jul 2012 LESS(1) 1610