{ "mode": "man", "parameter": "LESS", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/LESS/1/json", "generated": "2026-05-30T06:05:30Z", "synopsis": "", "sections": { "NAME": { "content": "less - opposite of more\n", "subsections": [] }, "SYNOPSIS": { "content": "", "subsections": [ { "name": "less -?", "content": "" }, { "name": "less --help", "content": "" }, { "name": "less -V", "content": "" }, { "name": "less --version", "content": "" }, { "name": "less [-[+]aABcCdeEfFgGiIJKLmMnNqQrRsSuUVwWX~]", "content": "[-b space] [-h lines] [-j line] [-k keyfile]\n[-{oO} logfile] [-p pattern] [-P prompt] [-t tag]\n[-T tagsfile] [-x tab,...] [-y lines] [-[z] lines]\n[-# shift] [+[+]cmd] [--] [filename]...\n(See the OPTIONS section for alternate option syntax with long option names.)\n" } ] }, "DESCRIPTION": { "content": "Less is a program similar to more(1), but it has many more features. Less does not have to\nread the entire input file before starting, so with large input files it starts up faster\nthan text editors like vi(1). Less uses termcap (or terminfo on some systems), so it can run\non a variety of terminals. There is even limited support for hardcopy terminals. (On a\nhardcopy terminal, lines which should be printed at the top of the screen are prefixed with a\ncaret.)\n\nCommands are based on both more and vi. Commands may be preceded by a decimal number, called\nN in the descriptions below. The number is used by some commands, as indicated.\n", "subsections": [] }, "COMMANDS": { "content": "In the following descriptions, ^X means control-X. ESC stands for the ESCAPE key; for exam‐\nple ESC-v means the two character sequence \"ESCAPE\", then \"v\".\n\nh or H Help: display a summary of these commands. If you forget all the other commands, re‐\nmember this one.\n\nSPACE or ^V or f or ^F\nScroll forward N lines, default one window (see option -z below). If N is more than\nthe screen size, only the final screenful is displayed. Warning: some systems use ^V\nas a special literalization character.\n\nz Like SPACE, but if N is specified, it becomes the new window size.\n\nESC-SPACE\nLike SPACE, but scrolls a full screenful, even if it reaches end-of-file in the\nprocess.\n\nENTER or RETURN or ^N or e or ^E or j or ^J\nScroll forward N lines, default 1. The entire N lines are displayed, even if N is\nmore than the screen size.\n\nd or ^D\nScroll forward N lines, default one half of the screen size. If N is specified, it\nbecomes the new default for subsequent d and u commands.\n\nb or ^B or ESC-v\nScroll backward N lines, default one window (see option -z below). If N is more than\nthe screen size, only the final screenful is displayed.\n\nw Like ESC-v, but if N is specified, it becomes the new window size.\n\ny or ^Y or ^P or k or ^K\nScroll backward N lines, default 1. The entire N lines are displayed, even if N is\nmore than the screen size. Warning: some systems use ^Y as a special job control\ncharacter.\n\nu or ^U\nScroll backward N lines, default one half of the screen size. If N is specified, it\nbecomes the new default for subsequent d and u commands.\n\nJ Like j, but continues to scroll beyond the end of the file.\n\nK or Y Like k, but continues to scroll beyond the beginning of the file.\n\nESC-) or RIGHTARROW\nScroll horizontally right N characters, default half the screen width (see the -# op‐\ntion). If a number N is specified, it becomes the default for future RIGHTARROW and\nLEFTARROW commands. While the text is scrolled, it acts as though the -S option (chop\nlines) were in effect.\n\nESC-( or LEFTARROW\nScroll horizontally left N characters, default half the screen width (see the -# op‐\ntion). If a number N is specified, it becomes the default for future RIGHTARROW and\nLEFTARROW commands.\n\nESC-} or ^RIGHTARROW\nScroll horizontally right to show the end of the longest displayed line.\n\nESC-{ or ^LEFTARROW\nScroll horizontally left back to the first column.\n\nr or ^R or ^L\nRepaint the screen.\n\nR Repaint the screen, discarding any buffered input. That is, reload the current file.\nUseful if the file is changing while it is being viewed.\n\nF Scroll forward, and keep trying to read when the end of file is reached. Normally\nthis command would be used when already at the end of the file. It is a way to moni‐\ntor the tail of a file which is growing while it is being viewed. (The behavior is\nsimilar to the \"tail -f\" command.) To stop waiting for more data, enter the interrupt\ncharacter (usually ^C). On some systems you can also use ^X.\n\nESC-F Like F, but as soon as a line is found which matches the last search pattern, the ter‐\nminal bell is rung and forward scrolling stops.\n\ng or < or ESC-<\nGo to line N in the file, default 1 (beginning of file). (Warning: this may be slow\nif N is large.)\n\nG or > or ESC->\nGo to line N in the file, default the end of the file. (Warning: this may be slow if\nN is large, or if N is not specified and standard input, rather than a file, is being\nread.)\n\nESC-G Same as G, except if no number N is specified and the input is standard input, goes to\nthe last line which is currently buffered.\n\np or % Go to a position N percent into the file. N should be between 0 and 100, and may con‐\ntain a decimal point.\n\nP Go to the line containing byte offset N in the file.\n\n{ If a left curly bracket appears in the top line displayed on the screen, the { command\nwill go to the matching right curly bracket. The matching right curly bracket is po‐\nsitioned on the bottom line of the screen. If there is more than one left curly\nbracket on the top line, a number N may be used to specify the N-th bracket on the\nline.\n\n} If a right curly bracket appears in the bottom line displayed on the screen, the }\ncommand will go to the matching left curly bracket. The matching left curly bracket\nis positioned on the top line of the screen. If there is more than one right curly\nbracket on the top line, a number N may be used to specify the N-th bracket on the\nline.\n\n( Like {, but applies to parentheses rather than curly brackets.\n\n) Like }, but applies to parentheses rather than curly brackets.\n\n[ Like {, but applies to square brackets rather than curly brackets.\n\n] Like }, but applies to square brackets rather than curly brackets.\n\nESC-^F Followed by two characters, acts like {, but uses the two characters as open and close\nbrackets, respectively. For example, \"ESC ^F < >\" could be used to go forward to the\n> which matches the < in the top displayed line.\n\nESC-^B Followed by two characters, acts like }, but uses the two characters as open and close\nbrackets, respectively. For example, \"ESC ^B < >\" could be used to go backward to the\n< which matches the > in the bottom displayed line.\n\nm Followed by any lowercase or uppercase letter, marks the first displayed line with\nthat letter. If the status column is enabled via the -J option, the status column\nshows the marked line.\n\nM Acts like m, except the last displayed line is marked rather than the first displayed\nline.\n\n' (Single quote.) Followed by any lowercase or uppercase letter, returns to the posi‐\ntion which was previously marked with that letter. Followed by another single quote,\nreturns to the position at which the last \"large\" movement command was executed. Fol‐\nlowed by a ^ or $, jumps to the beginning or end of the file respectively. Marks are\npreserved when a new file is examined, so the ' command can be used to switch between\ninput files.\n\n^X^X Same as single quote.\n\nESC-m Followed by any lowercase or uppercase letter, clears the mark identified by that let‐\nter.\n\n/pattern\nSearch forward in the file for the N-th line containing the pattern. N defaults to 1.\nThe pattern is a regular expression, as recognized by the regular expression library\nsupplied by your system. The search starts at the first line displayed (but see the\n-a and -j options, which change this).\n\nCertain characters are special if entered at the beginning of the pattern; they modify\nthe type of search rather than become part of the pattern:\n\n^N or !\nSearch for lines which do NOT match the pattern.\n\n^E or *\nSearch multiple files. That is, if the search reaches the END of the current\nfile without finding a match, the search continues in the next file in the com‐\nmand line list.\n\n^F or @\nBegin the search at the first line of the FIRST file in the command line list,\nregardless of what is currently displayed on the screen or the settings of the\n-a or -j options.\n\n^K Highlight any text which matches the pattern on the current screen, but don't\nmove to the first match (KEEP current position).\n\n^R Don't interpret regular expression metacharacters; that is, do a simple textual\ncomparison.\n\n^W WRAP around the current file. That is, if the search reaches the end of the\ncurrent file without finding a match, the search continues from the first line\nof the current file up to the line where it started.\n\n?pattern\nSearch backward in the file for the N-th line containing the pattern. The search\nstarts at the last line displayed (but see the -a and -j options, which change this).\n\nCertain characters are special as in the / command:\n\n^N or !\nSearch for lines which do NOT match the pattern.\n\n^E or *\nSearch multiple files. That is, if the search reaches the beginning of the\ncurrent file without finding a match, the search continues in the previous file\nin the command line list.\n\n^F or @\nBegin the search at the last line of the last file in the command line list,\nregardless of what is currently displayed on the screen or the settings of the\n-a or -j options.\n\n^K As in forward searches.\n\n^R As in forward searches.\n\n^W WRAP around the current file. That is, if the search reaches the beginning of\nthe current file without finding a match, the search continues from the last\nline of the current file up to the line where it started.\n\nESC-/pattern\nSame as \"/*\".\n\nESC-?pattern\nSame as \"?*\".\n\nn Repeat previous search, for N-th line containing the last pattern. If the previous\nsearch was modified by ^N, the search is made for the N-th line NOT containing the\npattern. If the previous search was modified by ^E, the search continues in the next\n(or previous) file if not satisfied in the current file. If the previous search was\nmodified by ^R, the search is done without using regular expressions. There is no ef‐\nfect if the previous search was modified by ^F or ^K.\n\nN Repeat previous search, but in the reverse direction.\n\nESC-n Repeat previous search, but crossing file boundaries. The effect is as if the previ‐\nous search were modified by *.\n\nESC-N Repeat previous search, but in the reverse direction and crossing file boundaries.\n\nESC-u Undo search highlighting. Turn off highlighting of strings matching the current\nsearch pattern. If highlighting is already off because of a previous ESC-u command,\nturn highlighting back on. Any search command will also turn highlighting back on.\n(Highlighting can also be disabled by toggling the -G option; in that case search com‐\nmands do not turn highlighting back on.)\n\nESC-U Like ESC-u but also clears the saved search pattern. If the status column is enabled\nvia the -J option, this clears all search matches marked in the status column.\n\n&pattern\nDisplay only lines which match the pattern; lines which do not match the pattern are\nnot displayed. If pattern is empty (if you type & immediately followed by ENTER), any\nfiltering is turned off, and all lines are displayed. While filtering is in effect,\nan ampersand is displayed at the beginning of the prompt, as a reminder that some\nlines in the file may be hidden. Multiple & commands may be entered, in which case\nonly lines which match all of the patterns will be displayed.\n\nCertain characters are special as in the / command:\n\n^N or !\nDisplay only lines which do NOT match the pattern.\n\n^R Don't interpret regular expression metacharacters; that is, do a simple textual\ncomparison.\n\n:e [filename]\nExamine a new file. If the filename is missing, the \"current\" file (see the :n and :p\ncommands below) from the list of files in the command line is re-examined. A percent\nsign (%) in the filename is replaced by the name of the current file. A pound sign\n(#) is replaced by the name of the previously examined file. However, two consecutive\npercent signs are simply replaced with a single percent sign. This allows you to en‐\nter a filename that contains a percent sign in the name. Similarly, two consecutive\npound signs are replaced with a single pound sign. The filename is inserted into the\ncommand line list of files so that it can be seen by subsequent :n and :p commands.\nIf the filename consists of several files, they are all inserted into the list of\nfiles and the first one is examined. If the filename contains one or more spaces, the\nentire filename should be enclosed in double quotes (also see the -\" option).\n\n^X^V or E\nSame as :e. Warning: some systems use ^V as a special literalization character. On\nsuch systems, you may not be able to use ^V.\n\n:n Examine the next file (from the list of files given in the command line). If a number\nN is specified, the N-th next file is examined.\n\n:p Examine the previous file in the command line list. If a number N is specified, the\nN-th previous file is examined.\n\n:x Examine the first file in the command line list. If a number N is specified, the N-th\nfile in the list is examined.\n\n:d Remove the current file from the list of files.\n\nt Go to the next tag, if there were more than one matches for the current tag. See the\n-t option for more details about tags.\n\nT Go to the previous tag, if there were more than one matches for the current tag.\n\n= or ^G or :f\nPrints some information about the file being viewed, including its name and the line\nnumber and byte offset of the bottom line being displayed. If possible, it also\nprints the length of the file, the number of lines in the file and the percent of the\nfile above the last displayed line.\n\n- Followed by one of the command line option letters (see OPTIONS below), this will\nchange the setting of that option and print a message describing the new setting. If\na ^P (CONTROL-P) is entered immediately after the dash, the setting of the option is\nchanged but no message is printed. If the option letter has a numeric value (such as\n-b or -h), or a string value (such as -P or -t), a new value may be entered after the\noption letter. If no new value is entered, a message describing the current setting\nis printed and nothing is changed.\n\n-- Like the - command, but takes a long option name (see OPTIONS below) rather than a\nsingle option letter. You must press ENTER or RETURN after typing the option name. A\n^P immediately after the second dash suppresses printing of a message describing the\nnew setting, as in the - command.\n\n-+ Followed by one of the command line option letters this will reset the option to its\ndefault setting and print a message describing the new setting. (The \"-+X\" command\ndoes the same thing as \"-+X\" on the command line.) This does not work for string-val‐\nued options.\n\n--+ Like the -+ command, but takes a long option name rather than a single option letter.\n\n-! Followed by one of the command line option letters, this will reset the option to the\n\"opposite\" of its default setting and print a message describing the new setting.\nThis does not work for numeric or string-valued options.\n\n--! Like the -! command, but takes a long option name rather than a single option letter.\n\n(Underscore.) Followed by one of the command line option letters, this will print a\nmessage describing the current setting of that option. The setting of the option is\nnot changed.\n\n(Double underscore.) Like the (underscore) command, but takes a long option name\nrather than a single option letter. You must press ENTER or RETURN after typing the\noption name.\n\n+cmd Causes the specified cmd to be executed each time a new file is examined. For exam‐\nple, +G causes less to initially display each file starting at the end rather than the\nbeginning.\n\nV Prints the version number of less being run.\n\nq or Q or :q or :Q or ZZ\nExits less.\n\nThe following four commands may or may not be valid, depending on your particular installa‐\ntion.\n\nv Invokes an editor to edit the current file being viewed. The editor is taken from the\nenvironment variable VISUAL if defined, or EDITOR if VISUAL is not defined, or de‐\nfaults to \"vi\" if neither VISUAL nor EDITOR is defined. See also the discussion of\nLESSEDIT under the section on PROMPTS below.\n\n! shell-command\nInvokes a shell to run the shell-command given. A percent sign (%) in the command is\nreplaced by the name of the current file. A pound sign (#) is replaced by the name of\nthe previously examined file. \"!!\" repeats the last shell command. \"!\" with no shell\ncommand simply invokes a shell. On Unix systems, the shell is taken from the environ‐\nment variable SHELL, or defaults to \"sh\". On MS-DOS and OS/2 systems, the shell is\nthe normal command processor.\n\n| shell-command\n represents any mark letter. Pipes a section of the input file to the given shell\ncommand. The section of the file to be piped is between the position marked by the\nletter and the current screen. The entire current screen is included, regardless of\nwhether the marked position is before or after the current screen. may also be ^\nor $ to indicate beginning or end of file respectively. If is . or newline, the\ncurrent screen is piped.\n\ns filename\nSave the input to a file. This only works if the input is a pipe, not an ordinary\nfile.\n", "subsections": [] }, "OPTIONS": { "content": "Command line options are described below. Most options may be changed while less is running,\nvia the \"-\" command.\n\nMost options may be given in one of two forms: either a dash followed by a single letter, or\ntwo dashes followed by a long option name. A long option name may be abbreviated as long as\nthe abbreviation is unambiguous. For example, --quit-at-eof may be abbreviated --quit, but\nnot --qui, since both --quit-at-eof and --quiet begin with --qui. Some long option names are\nin uppercase, such as --QUIT-AT-EOF, as distinct from --quit-at-eof. Such option names need\nonly have their first letter capitalized; the remainder of the name may be in either case.\nFor example, --Quit-at-eof is equivalent to --QUIT-AT-EOF.\n\nOptions are also taken from the environment variable \"LESS\". For example, to avoid typing\n\"less -options ...\" each time less is invoked, you might tell csh:\n\nsetenv LESS \"-options\"\n\nor if you use sh:\n\nLESS=\"-options\"; export LESS\n\nOn MS-DOS, you don't need the quotes, but you should replace any percent signs in the options\nstring by double percent signs.\n\nThe environment variable is parsed before the command line, so command line options override\nthe LESS environment variable. If an option appears in the LESS variable, it can be reset to\nits default value on the command line by beginning the command line option with \"-+\".\n\nSome options like -k or -D require a string to follow the option letter. The string for that\noption is considered to end when a dollar sign ($) is found. For example, you can set two -D\noptions on MS-DOS like this:\n\nLESS=\"Dn9.1$Ds4.1\"\n\nIf the --use-backslash option appears earlier in the options, then a dollar sign or backslash\nmay be included literally in an option string by preceding it with a backslash. If the\n--use-backslash option is not in effect, then backslashes are not treated specially, and\nthere is no way to include a dollar sign in the option string.\n\n-? or --help\nThis option displays a summary of the commands accepted by less (the same as the h\ncommand). (Depending on how your shell interprets the question mark, it may be neces‐\nsary to quote the question mark, thus: \"-\\?\".)\n\n-a or --search-skip-screen\nBy default, forward searches start at the top of the displayed screen and backwards\nsearches start at the bottom of the displayed screen (except for repeated searches in‐\nvoked by the n or N commands, which start after or before the \"target\" line respec‐\ntively; see the -j option for more about the target line). The -a option causes for‐\nward searches to instead start at the bottom of the screen and backward searches to\nstart at the top of the screen, thus skipping all lines displayed on the screen.\n\n-A or --SEARCH-SKIP-SCREEN\nCauses all forward searches (not just non-repeated searches) to start just after the\ntarget line, and all backward searches to start just before the target line. Thus,\nforward searches will skip part of the displayed screen (from the first line up to and\nincluding the target line). Similarly backwards searches will skip the displayed\nscreen from the last line up to and including the target line. This was the default\nbehavior in less versions prior to 441.\n\n-bn or --buffers=n\nSpecifies the amount of buffer space less will use for each file, in units of kilo‐\nbytes (1024 bytes). By default 64 KB of buffer space is used for each file (unless\nthe file is a pipe; see the -B option). The -b option specifies instead that n kilo‐\nbytes of buffer space should be used for each file. If n is -1, buffer space is un‐\nlimited; that is, the entire file can be read into memory.\n\n-B or --auto-buffers\nBy default, when data is read from a pipe, buffers are allocated automatically as\nneeded. If a large amount of data is read from the pipe, this can cause a large\namount of memory to be allocated. The -B option disables this automatic allocation of\nbuffers for pipes, so that only 64 KB (or the amount of space specified by the -b op‐\ntion) is used for the pipe. Warning: use of -B can result in erroneous display, since\nonly the most recently viewed part of the piped data is kept in memory; any earlier\ndata is lost.\n\n-c or --clear-screen\nCauses full screen repaints to be painted from the top line down. By default, full\nscreen repaints are done by scrolling from the bottom of the screen.\n\n-C or --CLEAR-SCREEN\nSame as -c, for compatibility with older versions of less.\n\n-d or --dumb\nThe -d option suppresses the error message normally displayed if the terminal is dumb;\nthat is, lacks some important capability, such as the ability to clear the screen or\nscroll backward. The -d option does not otherwise change the behavior of less on a\ndumb terminal.\n\n-Dxcolor or --color=xcolor\nChanges the color of different parts of the displayed text. x is a single character\nwhich selects the type of text whose color is being set:\n\nB Binary characters.\n\nC Control characters.\n\nE Errors and informational messages.\n\nM Mark letters in the status column.\n\nN Line numbers enabled via the -N option.\n\nP Prompts.\n\nR The rscroll character.\n\nS Search results.\n\nW The highlight enabled via the -w option.\n\nd Bold text.\n\nk Blinking text.\n\ns Standout text.\n\nu Underlined text.\n\nThe uppercase letters can be used only when the --use-color option is enabled. When\ntext color is specified by both an uppercase letter and a lowercase letter, the upper‐\ncase letter takes precedence. For example, error messages are normally displayed as\nstandout text. So if both \"s\" and \"E\" are given a color, the \"E\" color applies to er‐\nror messages, and the \"s\" color applies to other standout text. The \"d\" and \"u\" let‐\nters refer to bold and underline text formed by overstriking with backspaces (see the\n-u option), not to text using ANSI escape sequences with the -R option.\n\nA lowercase letter may be followed by a + to indicate that both the normal format\nchange and the specified color should both be used. For example, -Dug displays under‐\nlined text as green without underlining; the green color has replaced the usual under‐\nline formatting. But -Du+g displays underlined text as both green and in underlined\nformat.\n\ncolor is either a 4-bit color string or an 8-bit color string:\n\nA 4-bit color string is zero, one or two characters, where the first character speci‐\nfies the foreground color and the second specifies the background color as follows:\n\nb Blue\n\nc Cyan\n\ng Green\n\nk Black\n\nm Magenta\n\nr Red\n\nw White\n\ny Yellow\n\nThe corresponding upper-case letter denotes a brighter shade of the color. For exam‐\nple, -DNGk displays line numbers as bright green text on a black background, and -DEbR\ndisplays error messages as blue text on a bright red background. If either character\nis a \"-\" or is omitted, the corresponding color is set to that of normal text.\n\nAn 8-bit color string is one or two decimal integers separated by a dot, where the\nfirst integer specifies the foreground color and the second specifies the background\ncolor. Each integer is a value between 0 and 255 inclusive which selects a \"CSI 38;5\"\ncolor value (see\nhttps://en.wikipedia.org/wiki/ANSIescapecode#SGRparameters) If either integer is a\n\"-\" or is omitted, the corresponding color is set to that of normal text. On MS-DOS\nversions of less, 8-bit color is not supported; instead, decimal values are interpret‐\ned as 4-bit CHARINFO.Attributes values (see\nhttps://docs.microsoft.com/en-us/windows/console/char-info-str).\n\n-e or --quit-at-eof\nCauses less to automatically exit the second time it reaches end-of-file. By default,\nthe only way to exit less is via the \"q\" command.\n\n-E or --QUIT-AT-EOF\nCauses less to automatically exit the first time it reaches end-of-file.\n\n-f or --force\nForces non-regular files to be opened. (A non-regular file is a directory or a device\nspecial file.) Also suppresses the warning message when a binary file is opened. By\ndefault, less will refuse to open non-regular files. Note that some operating systems\nwill not allow directories to be read, even if -f is set.\n\n-F or --quit-if-one-screen\nCauses less to automatically exit if the entire file can be displayed on the first\nscreen.\n\n-g or --hilite-search\nNormally, less will highlight ALL strings which match the last search command. The -g\noption changes this behavior to highlight only the particular string which was found\nby the last search command. This can cause less to run somewhat faster than the de‐\nfault.\n\n-G or --HILITE-SEARCH\nThe -G option suppresses all highlighting of strings found by search commands.\n\n-hn or --max-back-scroll=n\nSpecifies a maximum number of lines to scroll backward. If it is necessary to scroll\nbackward more than n lines, the screen is repainted in a forward direction instead.\n(If the terminal does not have the ability to scroll backward, -h0 is implied.)\n\n-i or --ignore-case\nCauses searches to ignore case; that is, uppercase and lowercase are considered iden‐\ntical. This option is ignored if any uppercase letters appear in the search pattern;\nin other words, if a pattern contains uppercase letters, then that search does not ig‐\nnore case.\n\n-I or --IGNORE-CASE\nLike -i, but searches ignore case even if the pattern contains uppercase letters.\n\n-jn or --jump-target=n\nSpecifies a line on the screen where the \"target\" line is to be positioned. The tar‐\nget line is the line specified by any command to search for a pattern, jump to a line\nnumber, jump to a file percentage or jump to a tag. The screen line may be specified\nby a number: the top line on the screen is 1, the next is 2, and so on. The number\nmay be negative to specify a line relative to the bottom of the screen: the bottom\nline on the screen is -1, the second to the bottom is -2, and so on. Alternately, the\nscreen line may be specified as a fraction of the height of the screen, starting with\na decimal point: .5 is in the middle of the screen, .3 is three tenths down from the\nfirst line, and so on. If the line is specified as a fraction, the actual line number\nis recalculated if the terminal window is resized, so that the target line remains at\nthe specified fraction of the screen height. If any form of the -j option is used,\nrepeated forward searches (invoked with \"n\" or \"N\") begin at the line immediately af‐\nter the target line, and repeated backward searches begin at the target line, unless\nchanged by -a or -A. For example, if \"-j4\" is used, the target line is the fourth\nline on the screen, so forward searches begin at the fifth line on the screen. Howev‐\ner nonrepeated searches (invoked with \"/\" or \"?\") always begin at the start or end of\nthe current screen respectively.\n\n-J or --status-column\nDisplays a status column at the left edge of the screen. The status column shows the\nlines that matched the current search, and any lines that are marked (via the m or M\ncommand).\n\n-kfilename or --lesskey-file=filename\nCauses less to open and interpret the named file as a lesskey(1) binary file. Multi‐\nple -k options may be specified. If the LESSKEY or LESSKEYSYSTEM environment vari‐\nable is set, or if a lesskey file is found in a standard place (see KEY BINDINGS), it\nis also used as a lesskey file.\n\n--lesskey-src=filename\nCauses less to open and interpret the named file as a lesskey(1) source file. If the\nLESSKEYIN or LESSKEYINSYSTEM environment variable is set, or if a lesskey source file\nis found in a standard place (see KEY BINDINGS), it is also used as a lesskey source\nfile. Prior to version 582, the lesskey program needed to be run to convert a lesskey\nsource file to a lesskey binary file for less to use. Newer versions of less read the\nlesskey source file directly and ignore the binary file if the source file exists.\n\n-K or --quit-on-intr\nCauses less to exit immediately (with status 2) when an interrupt character (usually\n^C) is typed. Normally, an interrupt character causes less to stop whatever it is do‐\ning and return to its command prompt. Note that use of this option makes it impossi‐\nble to return to the command prompt from the \"F\" command.\n\n-L or --no-lessopen\nIgnore the LESSOPEN environment variable (see the INPUT PREPROCESSOR section below).\nThis option can be set from within less, but it will apply only to files opened subse‐\nquently, not to the file which is currently open.\n\n-m or --long-prompt\nCauses less to prompt verbosely (like more), with the percent into the file. By de‐\nfault, less prompts with a colon.\n\n-M or --LONG-PROMPT\nCauses less to prompt even more verbosely than more.\n\n-n or --line-numbers\nSuppresses line numbers. The default (to use line numbers) may cause less to run more\nslowly in some cases, especially with a very large input file. Suppressing line num‐\nbers with the -n option will avoid this problem. Using line numbers means: the line\nnumber will be displayed in the verbose prompt and in the = command, and the v command\nwill pass the current line number to the editor (see also the discussion of LESSEDIT\nin PROMPTS below).\n\n-N or --LINE-NUMBERS\nCauses a line number to be displayed at the beginning of each line in the display.\n\n-ofilename or --log-file=filename\nCauses less to copy its input to the named file as it is being viewed. This applies\nonly when the input file is a pipe, not an ordinary file. If the file already exists,\nless will ask for confirmation before overwriting it.\n\n-Ofilename or --LOG-FILE=filename\nThe -O option is like -o, but it will overwrite an existing file without asking for\nconfirmation.\n\nIf no log file has been specified, the -o and -O options can be used from within less\nto specify a log file. Without a file name, they will simply report the name of the\nlog file. The \"s\" command is equivalent to specifying -o from within less.\n\n-ppattern or --pattern=pattern\nThe -p option on the command line is equivalent to specifying +/pattern; that is, it\ntells less to start at the first occurrence of pattern in the file.\n\n-Pprompt or --prompt=prompt\nProvides a way to tailor the three prompt styles to your own preference. This option\nwould normally be put in the LESS environment variable, rather than being typed in\nwith each less command. Such an option must either be the last option in the LESS\nvariable, or be terminated by a dollar sign.\n-Ps followed by a string changes the default (short) prompt to that string.\n-Pm changes the medium (-m) prompt.\n-PM changes the long (-M) prompt.\n-Ph changes the prompt for the help screen.\n-P= changes the message printed by the = command.\n-Pw changes the message printed while waiting for data (in the F command).\n\nAll prompt strings consist of a sequence of letters and special escape sequences. See\nthe section on PROMPTS for more details.\n\n-q or --quiet or --silent\nCauses moderately \"quiet\" operation: the terminal bell is not rung if an attempt is\nmade to scroll past the end of the file or before the beginning of the file. If the\nterminal has a \"visual bell\", it is used instead. The bell will be rung on certain\nother errors, such as typing an invalid character. The default is to ring the termi‐\nnal bell in all such cases.\n\n-Q or --QUIET or --SILENT\nCauses totally \"quiet\" operation: the terminal bell is never rung. If the terminal\nhas a \"visual bell\", it is used in all cases where the terminal bell would have been\nrung.\n\n-r or --raw-control-chars\nCauses \"raw\" control characters to be displayed. The default is to display control\ncharacters using the caret notation; for example, a control-A (octal 001) is displayed\nas \"^A\". Warning: when the -r option is used, less cannot keep track of the actual\nappearance of the screen (since this depends on how the screen responds to each type\nof control character). Thus, various display problems may result, such as long lines\nbeing split in the wrong place.\n\nUSE OF THE -r OPTION IS NOT RECOMMENDED.\n\n-R or --RAW-CONTROL-CHARS\nLike -r, but only ANSI \"color\" escape sequences and OSC 8 hyperlink sequences are out‐\nput in \"raw\" form. Unlike -r, the screen appearance is maintained correctly, provided\nthat there are no escape sequences in the file other than these types of escape se‐\nquences. Color escape sequences are only supported when the color is changed within\none line, not across lines. In other words, the beginning of each line is assumed to\nbe normal (non-colored), regardless of any escape sequences in previous lines. For\nthe purpose of keeping track of screen appearance, these escape sequences are assumed\nto not move the cursor.\n\nOSC 8 hyperlinks are sequences of the form:\n\nESC ] 8 ; ... \\7\n\nThe terminating sequence may be either a BEL character (\\7) or the two-character se‐\nquence \"ESC \\\".\n\nANSI color escape sequences are sequences of the form:\n\nESC [ ... m\n\nwhere the \"...\" is zero or more color specification characters. You can make less\nthink that characters other than \"m\" can end ANSI color escape sequences by setting\nthe environment variable LESSANSIENDCHARS to the list of characters which can end a\ncolor escape sequence. And you can make less think that characters other than the\nstandard ones may appear between the ESC and the m by setting the environment variable\nLESSANSIMIDCHARS to the list of characters which can appear.\n\n-s or --squeeze-blank-lines\nCauses consecutive blank lines to be squeezed into a single blank line. This is use‐\nful when viewing nroff output.\n\n-S or --chop-long-lines\nCauses lines longer than the screen width to be chopped (truncated) rather than\nwrapped. That is, the portion of a long line that does not fit in the screen width is\nnot displayed until you press RIGHT-ARROW. The default is to wrap long lines; that\nis, display the remainder on the next line.\n\n-ttag or --tag=tag\nThe -t option, followed immediately by a TAG, will edit the file containing that tag.\nFor this to work, tag information must be available; for example, there may be a file\nin the current directory called \"tags\", which was previously built by ctags(1) or an\nequivalent command. If the environment variable LESSGLOBALTAGS is set, it is taken to\nbe the name of a command compatible with global(1), and that command is executed to\nfind the tag. (See http://www.gnu.org/software/global/global.html). The -t option\nmay also be specified from within less (using the - command) as a way of examining a\nnew file. The command \":t\" is equivalent to specifying -t from within less.\n\n-Ttagsfile or --tag-file=tagsfile\nSpecifies a tags file to be used instead of \"tags\".\n\n-u or --underline-special\nCauses backspaces and carriage returns to be treated as printable characters; that is,\nthey are sent to the terminal when they appear in the input.\n\n-U or --UNDERLINE-SPECIAL\nCauses backspaces, tabs, carriage returns and \"formatting characters\" (as defined by\nUnicode) to be treated as control characters; that is, they are handled as specified\nby the -r option.\n\nBy default, if neither -u nor -U is given, backspaces which appear adjacent to an un‐\nderscore character are treated specially: the underlined text is displayed using the\nterminal's hardware underlining capability. Also, backspaces which appear between two\nidentical characters are treated specially: the overstruck text is printed using the\nterminal's hardware boldface capability. Other backspaces are deleted, along with the\npreceding character. Carriage returns immediately followed by a newline are deleted.\nOther carriage returns are handled as specified by the -r option. Unicode formatting\ncharacters, such as the Byte Order Mark, are sent to the terminal. Text which is\noverstruck or underlined can be searched for if neither -u nor -U is in effect.\n\n-V or --version\nDisplays the version number of less.\n\n-w or --hilite-unread\nTemporarily highlights the first \"new\" line after a forward movement of a full page.\nThe first \"new\" line is the line immediately following the line previously at the bot‐\ntom of the screen. Also highlights the target line after a g or p command. The high‐\nlight is removed at the next command which causes movement. The entire line is high‐\nlighted, unless the -J option is in effect, in which case only the status column is\nhighlighted.\n\n-W or --HILITE-UNREAD\nLike -w, but temporarily highlights the first new line after any forward movement com‐\nmand larger than one line.\n\n-xn,... or --tabs=n,...\nSets tab stops. If only one n is specified, tab stops are set at multiples of n. If\nmultiple values separated by commas are specified, tab stops are set at those posi‐\ntions, and then continue with the same spacing as the last two. For example, -x9,17\nwill set tabs at positions 9, 17, 25, 33, etc. The default for n is 8.\n\n-X or --no-init\nDisables sending the termcap initialization and deinitialization strings to the termi‐\nnal. This is sometimes desirable if the deinitialization string does something unnec‐\nessary, like clearing the screen.\n\n-yn or --max-forw-scroll=n\nSpecifies a maximum number of lines to scroll forward. If it is necessary to scroll\nforward more than n lines, the screen is repainted instead. The -c or -C option may\nbe used to repaint from the top of the screen if desired. By default, any forward\nmovement causes scrolling.\n\n-zn or --window=n or -n\nChanges the default scrolling window size to n lines. The default is one screenful.\nThe z and w commands can also be used to change the window size. The \"z\" may be omit‐\nted for compatibility with some versions of more. If the number n is negative, it in‐\ndicates n lines less than the current screen size. For example, if the screen is 24\nlines, -z-4 sets the scrolling window to 20 lines. If the screen is resized to 40\nlines, the scrolling window automatically changes to 36 lines.\n\n-\"cc or --quotes=cc\nChanges the filename quoting character. This may be necessary if you are trying to\nname a file which contains both spaces and quote characters. Followed by a single\ncharacter, this changes the quote character to that character. Filenames containing a\nspace should then be surrounded by that character rather than by double quotes. Fol‐\nlowed by two characters, changes the open quote to the first character, and the close\nquote to the second character. Filenames containing a space should then be preceded\nby the open quote character and followed by the close quote character. Note that even\nafter the quote characters are changed, this option remains -\" (a dash followed by a\ndouble quote).\n\n-~ or --tilde\nNormally lines after end of file are displayed as a single tilde (~). This option\ncauses lines after end of file to be displayed as blank lines.\n\n-# or --shift\nSpecifies the default number of positions to scroll horizontally in the RIGHTARROW and\nLEFTARROW commands. If the number specified is zero, it sets the default number of\npositions to one half of the screen width. Alternately, the number may be specified\nas a fraction of the width of the screen, starting with a decimal point: .5 is half of\nthe screen width, .3 is three tenths of the screen width, and so on. If the number is\nspecified as a fraction, the actual number of scroll positions is recalculated if the\nterminal window is resized, so that the actual scroll remains at the specified frac‐\ntion of the screen width.\n", "subsections": [ { "name": "--file-size", "content": "If --file-size is specified, less will determine the size of the file immediately af‐\nter opening the file. Normally this is not done, because it can be slow if the input\nfile is large.\n", "long": "--file-size" }, { "name": "--follow-name", "content": "Normally, if the input file is renamed while an F command is executing, less will con‐\ntinue to display the contents of the original file despite its name change. If --fol‐\nlow-name is specified, during an F command less will periodically attempt to reopen\nthe file by name. If the reopen succeeds and the file is a different file from the\noriginal (which means that a new file has been created with the same name as the orig‐\ninal (now renamed) file), less will display the contents of that new file.\n", "long": "--follow-name" }, { "name": "--incsearch", "content": "Subsequent search commands will be \"incremental\"; that is, less will advance to the\nnext line containing the search pattern as each character of the pattern is typed in.\n", "long": "--incsearch" }, { "name": "--line-num-width", "content": "Sets the minimum width of the line number field when the -N option is in effect. The\ndefault is 7 characters.\n", "long": "--line-num-width" }, { "name": "--mouse", "content": "Enables mouse input: scrolling the mouse wheel down moves forward in the file,\nscrolling the mouse wheel up moves backwards in the file, and clicking the mouse sets\nthe \"#\" mark to the line where the mouse is clicked. The number of lines to scroll\nwhen the wheel is moved can be set by the --wheel-lines option. Mouse input works on‐\nly on terminals which support X11 mouse reporting, and on the Windows version of less.\n", "long": "--mouse" }, { "name": "--MOUSE", "content": "Like --mouse, except the direction scrolled on mouse wheel movement is reversed.\n", "long": "--MOUSE" }, { "name": "--no-keypad", "content": "Disables sending the keypad initialization and deinitialization strings to the termi‐\nnal. This is sometimes useful if the keypad strings make the numeric keypad behave in\nan undesirable manner.\n", "long": "--no-keypad" }, { "name": "--no-histdups", "content": "This option changes the behavior so that if a search string or file name is typed in,\nand the same string is already in the history list, the existing copy is removed from\nthe history list before the new one is added. Thus, a given string will appear only\nonce in the history list. Normally, a string may appear multiple times.\n", "long": "--no-histdups" }, { "name": "--rscroll", "content": "This option changes the character used to mark truncated lines. It may begin with a\ntwo-character attribute indicator like LESSBINFMT does. If there is no attribute in‐\ndicator, standout is used. If set to \"-\", truncated lines are not marked.\n", "long": "--rscroll" }, { "name": "--save-marks", "content": "Save marks in the history file, so marks are retained across different invocations of\nless.\n", "long": "--save-marks" }, { "name": "--status-col-width", "content": "Sets the width of the status column when the -J option is in effect. The default is 2\ncharacters.\n", "long": "--status-col-width" }, { "name": "--use-backslash", "content": "This option changes the interpretations of options which follow this one. After the\n--use-backslash option, any backslash in an option string is removed and the following\ncharacter is taken literally. This allows a dollar sign to be included in option\nstrings.\n", "long": "--use-backslash" }, { "name": "--use-color", "content": "Enables the colored text in various places. The -D option can be used to change the\ncolors. Colored text works only if the terminal supports ANSI color escape sequences\n(as defined in ECMA-48 SGR; see\nhttps://www.ecma-international.org/publications-and-standards/standards/ecma-48).\n\n--wheel-lines=n\nSet the number of lines to scroll when the mouse wheel is scrolled and the --mouse or\n--MOUSE option is in effect. The default is 1 line.\n\n-- A command line argument of \"--\" marks the end of option arguments. Any arguments fol‐\nlowing this are interpreted as filenames. This can be useful when viewing a file\nwhose name begins with a \"-\" or \"+\".\n\n+ If a command line option begins with +, the remainder of that option is taken to be an\ninitial command to less. For example, +G tells less to start at the end of the file\nrather than the beginning, and +/xyz tells it to start at the first occurrence of\n\"xyz\" in the file. As a special case, + acts like +g; that is, it\nstarts the display at the specified line number (however, see the caveat under the \"g\"\ncommand above). If the option starts with ++, the initial command applies to every\nfile being viewed, not just the first one. The + command described previously may al‐\nso be used to set (or change) an initial command for every file.\n", "long": "--use-color" } ] }, "LINE EDITING": { "content": "When entering a command line at the bottom of the screen (for example, a filename for the :e\ncommand, or the pattern for a search command), certain keys can be used to manipulate the\ncommand line. Most commands have an alternate form in [ brackets ] which can be used if a\nkey does not exist on a particular keyboard. (Note that the forms beginning with ESC do not\nwork in some MS-DOS and Windows systems because ESC is the line erase character.) Any of\nthese special keys may be entered literally by preceding it with the \"literal\" character, ei‐\nther ^V or ^A. A backslash itself may also be entered literally by entering two backslashes.\n\nLEFTARROW [ ESC-h ]\nMove the cursor one space to the left.\n\nRIGHTARROW [ ESC-l ]\nMove the cursor one space to the right.\n\n^LEFTARROW [ ESC-b or ESC-LEFTARROW ]\n(That is, CONTROL and LEFTARROW simultaneously.) Move the cursor one word to the\nleft.\n\n^RIGHTARROW [ ESC-w or ESC-RIGHTARROW ]\n(That is, CONTROL and RIGHTARROW simultaneously.) Move the cursor one word to the\nright.\n\nHOME [ ESC-0 ]\nMove the cursor to the beginning of the line.\n\nEND [ ESC-$ ]\nMove the cursor to the end of the line.\n\nBACKSPACE\nDelete the character to the left of the cursor, or cancel the command if the command\nline is empty.\n\nDELETE or [ ESC-x ]\nDelete the character under the cursor.\n\n^BACKSPACE [ ESC-BACKSPACE ]\n(That is, CONTROL and BACKSPACE simultaneously.) Delete the word to the left of the\ncursor.\n\n^DELETE [ ESC-X or ESC-DELETE ]\n(That is, CONTROL and DELETE simultaneously.) Delete the word under the cursor.\n\nUPARROW [ ESC-k ]\nRetrieve the previous command line. If you first enter some text and then press UPAR‐\nROW, it will retrieve the previous command which begins with that text.\n\nDOWNARROW [ ESC-j ]\nRetrieve the next command line. If you first enter some text and then press DOWNAR‐\nROW, it will retrieve the next command which begins with that text.\n\nTAB Complete the partial filename to the left of the cursor. If it matches more than one\nfilename, the first match is entered into the command line. Repeated TABs will cycle\nthru the other matching filenames. If the completed filename is a directory, a \"/\" is\nappended to the filename. (On MS-DOS systems, a \"\\\" is appended.) The environment\nvariable LESSSEPARATOR can be used to specify a different character to append to a di‐\nrectory name.\n\nBACKTAB [ ESC-TAB ]\nLike, TAB, but cycles in the reverse direction thru the matching filenames.\n\n^L Complete the partial filename to the left of the cursor. If it matches more than one\nfilename, all matches are entered into the command line (if they fit).\n\n^U (Unix and OS/2) or ESC (MS-DOS)\nDelete the entire command line, or cancel the command if the command line is empty.\nIf you have changed your line-kill character in Unix to something other than ^U, that\ncharacter is used instead of ^U.\n\n^G Delete the entire command line and return to the main prompt.\n", "subsections": [] }, "KEY BINDINGS": { "content": "You may define your own less commands by creating a lesskey source file. This file specifies\na set of command keys and an action associated with each key. You may also change the line-\nediting keys (see LINE EDITING), and to set environment variables. If the environment vari‐\nable LESSKEYIN is set, less uses that as the name of the lesskey source file. Otherwise,\nless looks in a standard place for the lesskey source file: On Unix systems, less looks for a\nlesskey file called \"$XDGCONFIGHOME/lesskey\" or \"$HOME/.lesskey\". On MS-DOS and Windows\nsystems, less looks for a lesskey file called \"$HOME/lesskey\", and if it is not found there,\nthen looks for a lesskey file called \"lesskey\" in any directory specified in the PATH envi‐\nronment variable. On OS/2 systems, less looks for a lesskey file called \"$HOME/lesskey.ini\",\nand if it is not found, then looks for a lesskey file called \"lesskey.ini\" in any directory\nspecified in the INIT environment variable, and if it not found there, then looks for a\nlesskey file called \"lesskey.ini\" in any directory specified in the PATH environment vari‐\nable. See the lesskey manual page for more details.\n\nA system-wide lesskey source file may also be set up to provide key bindings. If a key is\ndefined in both a local lesskey file and in the system-wide file, key bindings in the local\nfile take precedence over those in the system-wide file. If the environment variable\nLESSKEYINSYSTEM is set, less uses that as the name of the system-wide lesskey file. Other‐\nwise, less looks in a standard place for the system-wide lesskey file: On Unix systems, the\nsystem-wide lesskey file is /usr/local/etc/syslesskey. (However, if less was built with a\ndifferent sysconf directory than /usr/local/etc, that directory is where the sysless file is\nfound.) On MS-DOS and Windows systems, the system-wide lesskey file is c:\\syslesskey. On\nOS/2 systems, the system-wide lesskey file is c:\\syslesskey.ini.\n\nPrevious versions of less (before v582) used lesskey files with a binary format, produced by\nthe lesskey program. It is no longer necessary to use the lesskey program.\n", "subsections": [] }, "INPUT PREPROCESSOR": { "content": "You may define an \"input preprocessor\" for less. Before less opens a file, it first gives\nyour input preprocessor a chance to modify the way the contents of the file are displayed.\nAn input preprocessor is simply an executable program (or shell script), which writes the\ncontents of the file to a different file, called the replacement file. The contents of the\nreplacement file are then displayed in place of the contents of the original file. However,\nit will appear to the user as if the original file is opened; that is, less will display the\noriginal filename as the name of the current file.\n\nAn input preprocessor receives one command line argument, the original filename, as entered\nby the user. It should create the replacement file, and when finished, print the name of the\nreplacement file to its standard output. If the input preprocessor does not output a re‐\nplacement filename, less uses the original file, as normal. The input preprocessor is not\ncalled when viewing standard input. To set up an input preprocessor, set the LESSOPEN envi‐\nronment variable to a command line which will invoke your input preprocessor. This command\nline should include one occurrence of the string \"%s\", which will be replaced by the filename\nwhen the input preprocessor command is invoked.\n\nWhen less closes a file opened in such a way, it will call another program, called the input\npostprocessor, which may perform any desired clean-up action (such as deleting the replace‐\nment file created by LESSOPEN). This program receives two command line arguments, the origi‐\nnal filename as entered by the user, and the name of the replacement file. To set up an in‐\nput postprocessor, set the LESSCLOSE environment variable to a command line which will invoke\nyour input postprocessor. It may include two occurrences of the string \"%s\"; the first is\nreplaced with the original name of the file and the second with the name of the replacement\nfile, which was output by LESSOPEN.\n\nFor example, on many Unix systems, these two scripts will allow you to keep files in com‐\npressed format, but still let less view them directly:\n\nlessopen.sh:\n#! /bin/sh\ncase \"$1\" in\n*.Z) TEMPFILE=$(mktemp)\nuncompress -c $1 >$TEMPFILE 2>/dev/null\nif [ -s $TEMPFILE ]; then\necho $TEMPFILE\nelse\nrm -f $TEMPFILE\nfi\n;;\nesac\n\nlessclose.sh:\n#! /bin/sh\nrm $2\n\nTo use these scripts, put them both where they can be executed and set\nLESSOPEN=\"lessopen.sh %s\", and LESSCLOSE=\"lessclose.sh %s %s\". More complex LESSOPEN and\nLESSCLOSE scripts may be written to accept other types of compressed files, and so on.\n\nIt is also possible to set up an input preprocessor to pipe the file data directly to less,\nrather than putting the data into a replacement file. This avoids the need to decompress the\nentire file before starting to view it. An input preprocessor that works this way is called\nan input pipe. An input pipe, instead of writing the name of a replacement file on its stan‐\ndard output, writes the entire contents of the replacement file on its standard output. If\nthe input pipe does not write any characters on its standard output, then there is no re‐\nplacement file and less uses the original file, as normal. To use an input pipe, make the\nfirst character in the LESSOPEN environment variable a vertical bar (|) to signify that the\ninput preprocessor is an input pipe. As with non-pipe input preprocessors, the command\nstring must contain one occurrence of %s, which is replaced with the filename of the input\nfile.\n\nFor example, on many Unix systems, this script will work like the previous example scripts:\n\nlesspipe.sh:\n#! /bin/sh\ncase \"$1\" in\n*.Z) uncompress -c $1 2>/dev/null\n;;\n*) exit 1\n;;\nesac\nexit $?\n\nTo use this script, put it where it can be executed and set LESSOPEN=\"|lesspipe.sh %s\".\n\nNote that a preprocessor cannot output an empty file, since that is interpreted as meaning\nthere is no replacement, and the original file is used. To avoid this, if LESSOPEN starts\nwith two vertical bars, the exit status of the script becomes meaningful. If the exit status\nis zero, the output is considered to be replacement text, even if it is empty. If the exit\nstatus is nonzero, any output is ignored and the original file is used. For compatibility\nwith previous versions of less, if LESSOPEN starts with only one vertical bar, the exit sta‐\ntus of the preprocessor is ignored.\n\nWhen an input pipe is used, a LESSCLOSE postprocessor can be used, but it is usually not nec‐\nessary since there is no replacement file to clean up. In this case, the replacement file\nname passed to the LESSCLOSE postprocessor is \"-\".\n\nFor compatibility with previous versions of less, the input preprocessor or pipe is not used\nif less is viewing standard input. However, if the first character of LESSOPEN is a dash\n(-), the input preprocessor is used on standard input as well as other files. In this case,\nthe dash is not considered to be part of the preprocessor command. If standard input is be‐\ning viewed, the input preprocessor is passed a file name consisting of a single dash. Simi‐\nlarly, if the first two characters of LESSOPEN are vertical bar and dash (|-) or two vertical\nbars and a dash (||-), the input pipe is used on standard input as well as other files.\nAgain, in this case the dash is not considered to be part of the input pipe command.\n", "subsections": [] }, "NATIONAL CHARACTER SETS": { "content": "There are three types of characters in the input file:\n\nnormal characters\ncan be displayed directly to the screen.\n\ncontrol characters\nshould not be displayed directly, but are expected to be found in ordinary text files\n(such as backspace and tab).\n\nbinary characters\nshould not be displayed directly and are not expected to be found in text files.\n\nA \"character set\" is simply a description of which characters are to be considered normal,\ncontrol, and binary. The LESSCHARSET environment variable may be used to select a character\nset. Possible values for LESSCHARSET are:\n\nascii BS, TAB, NL, CR, and formfeed are control characters, all chars with values between 32\nand 126 are normal, and all others are binary.\n\niso8859\nSelects an ISO 8859 character set. This is the same as ASCII, except characters be‐\ntween 160 and 255 are treated as normal characters.\n\nlatin1 Same as iso8859.\n\nlatin9 Same as iso8859.\n\ndos Selects a character set appropriate for MS-DOS.\n\nebcdic Selects an EBCDIC character set.\n\nIBM-1047\nSelects an EBCDIC character set used by OS/390 Unix Services. This is the EBCDIC ana‐\nlogue of latin1. You get similar results by setting either LESSCHARSET=IBM-1047 or\nLCCTYPE=enUS in your environment.\n\nkoi8-r Selects a Russian character set.\n\nnext Selects a character set appropriate for NeXT computers.\n\nutf-8 Selects the UTF-8 encoding of the ISO 10646 character set. UTF-8 is special in that\nit supports multi-byte characters in the input file. It is the only character set\nthat supports multi-byte characters.\n\nwindows\nSelects a character set appropriate for Microsoft Windows (cp 1251).\n\nIn rare cases, it may be desired to tailor less to use a character set other than the ones\ndefinable by LESSCHARSET. In this case, the environment variable LESSCHARDEF can be used to\ndefine a character set. It should be set to a string where each character in the string rep‐\nresents one character in the character set. The character \".\" is used for a normal charac‐\nter, \"c\" for control, and \"b\" for binary. A decimal number may be used for repetition. For\nexample, \"bccc4b.\" would mean character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7\nare binary, and 8 is normal. All characters after the last are taken to be the same as the\nlast, so characters 9 through 255 would be normal. (This is an example, and does not neces‐\nsarily represent any real character set.)\n\nThis table shows the value of LESSCHARDEF which is equivalent to each of the possible values\nfor LESSCHARSET:\n\nascii 8bcccbcc18b95.b\ndos 8bcccbcc12bc5b95.b.\nebcdic 5bc6bcc7bcc41b.9b7.9b5.b..8b6.10b6.b9.7b\n9.8b8.17b3.3b9.7b9.8b8.6b10.b.b.b.\nIBM-1047 4cbcbc3b9cbccbccbb4c6bcc5b3cbbc4bc4bccbc\n191.b\niso8859 8bcccbcc18b95.33b.\nkoi8-r 8bcccbcc18b95.b128.\nlatin1 8bcccbcc18b95.33b.\nnext 8bcccbcc18b95.bb125.bb\n\nIf neither LESSCHARSET nor LESSCHARDEF is set, but any of the strings \"UTF-8\", \"UTF8\",\n\"utf-8\" or \"utf8\" is found in the LCALL, LCCTYPE or LANG environment variables, then the\ndefault character set is utf-8.\n\nIf that string is not found, but your system supports the setlocale interface, less will use\nsetlocale to determine the character set. setlocale is controlled by setting the LANG or\nLCCTYPE environment variables.\n\nFinally, if the setlocale interface is also not available, the default character set is\nlatin1.\n\nControl and binary characters are displayed in standout (reverse video). Each such character\nis displayed in caret notation if possible (e.g. ^A for control-A). Caret notation is used\nonly if inverting the 0100 bit results in a normal printable character. Otherwise, the char‐\nacter is displayed as a hex number in angle brackets. This format can be changed by setting\nthe LESSBINFMT environment variable. LESSBINFMT may begin with a \"*\" and one character to\nselect the display attribute: \"*k\" is blinking, \"*d\" is bold, \"*u\" is underlined, \"*s\" is\nstandout, and \"*n\" is normal. If LESSBINFMT does not begin with a \"*\", normal attribute is\nassumed. The remainder of LESSBINFMT is a string which may include one printf-style escape\nsequence (a % followed by x, X, o, d, etc.). For example, if LESSBINFMT is \"*u[%x]\", binary\ncharacters are displayed in underlined hexadecimal surrounded by brackets. The default if no\nLESSBINFMT is specified is \"*s<%02X>\". Warning: the result of expanding the character via\nLESSBINFMT must be less than 31 characters.\n\nWhen the character set is utf-8, the LESSUTFBINFMT environment variable acts similarly to\nLESSBINFMT but it applies to Unicode code points that were successfully decoded but are un‐\nsuitable for display (e.g., unassigned code points). Its default value is \"\". Note\nthat LESSUTFBINFMT and LESSBINFMT share their display attribute setting (\"*x\") so specifying\none will affect both; LESSUTFBINFMT is read after LESSBINFMT so its setting, if any, will\nhave priority. Problematic octets in a UTF-8 file (octets of a truncated sequence, octets of\na complete but non-shortest form sequence, invalid octets, and stray trailing octets) are\ndisplayed individually using LESSBINFMT so as to facilitate diagnostic of how the UTF-8 file\nis ill-formed.\n", "subsections": [] }, "PROMPTS": { "content": "The -P option allows you to tailor the prompt to your preference. The string given to the -P\noption replaces the specified prompt string. Certain characters in the string are interpret‐\ned specially. The prompt mechanism is rather complicated to provide flexibility, but the or‐\ndinary user need not understand the details of constructing personalized prompt strings.\n\nA percent sign followed by a single character is expanded according to what the following\ncharacter is:\n\n%bX Replaced by the byte offset into the current input file. The b is followed by a sin‐\ngle character (shown as X above) which specifies the line whose byte offset is to be\nused. If the character is a \"t\", the byte offset of the top line in the display is\nused, an \"m\" means use the middle line, a \"b\" means use the bottom line, a \"B\" means\nuse the line just after the bottom line, and a \"j\" means use the \"target\" line, as\nspecified by the -j option.\n\n%B Replaced by the size of the current input file.\n\n%c Replaced by the column number of the text appearing in the first column of the screen.\n\n%dX Replaced by the page number of a line in the input file. The line to be used is de‐\ntermined by the X, as with the %b option.\n\n%D Replaced by the number of pages in the input file, or equivalently, the page number of\nthe last line in the input file.\n\n%E Replaced by the name of the editor (from the VISUAL environment variable, or the EDI‐\nTOR environment variable if VISUAL is not defined). See the discussion of the LESSED‐\nIT feature below.\n\n%f Replaced by the name of the current input file.\n\n%F Replaced by the last component of the name of the current input file.\n\n%g Replaced by the shell-escaped name of the current input file. This is useful when the\nexpanded string will be used in a shell command, such as in LESSEDIT.\n\n%i Replaced by the index of the current file in the list of input files.\n\n%lX Replaced by the line number of a line in the input file. The line to be used is de‐\ntermined by the X, as with the %b option.\n\n%L Replaced by the line number of the last line in the input file.\n\n%m Replaced by the total number of input files.\n\n%pX Replaced by the percent into the current input file, based on byte offsets. The line\nused is determined by the X as with the %b option.\n\n%PX Replaced by the percent into the current input file, based on line numbers. The line\nused is determined by the X as with the %b option.\n\n%s Same as %B.\n\n%t Causes any trailing spaces to be removed. Usually used at the end of the string, but\nmay appear anywhere.\n\n%T Normally expands to the word \"file\". However if viewing files via a tags list using\nthe -t option, it expands to the word \"tag\".\n\n%x Replaced by the name of the next input file in the list.\n\nIf any item is unknown (for example, the file size if input is a pipe), a question mark is\nprinted instead.\n\nThe format of the prompt string can be changed depending on certain conditions. A question\nmark followed by a single character acts like an \"IF\": depending on the following character,\na condition is evaluated. If the condition is true, any characters following the question\nmark and condition character, up to a period, are included in the prompt. If the condition\nis false, such characters are not included. A colon appearing between the question mark and\nthe period can be used to establish an \"ELSE\": any characters between the colon and the peri‐\nod are included in the string if and only if the IF condition is false. Condition characters\n(which follow a question mark) may be:\n\n?a True if any characters have been included in the prompt so far.\n\n?bX True if the byte offset of the specified line is known.\n\n?B True if the size of current input file is known.\n\n?c True if the text is horizontally shifted (%c is not zero).\n\n?dX True if the page number of the specified line is known.\n\n?e True if at end-of-file.\n\n?f True if there is an input filename (that is, if input is not a pipe).\n\n?lX True if the line number of the specified line is known.\n\n?L True if the line number of the last line in the file is known.\n\n?m True if there is more than one input file.\n\n?n True if this is the first prompt in a new input file.\n\n?pX True if the percent into the current input file, based on byte offsets, of the speci‐\nfied line is known.\n\n?PX True if the percent into the current input file, based on line numbers, of the speci‐\nfied line is known.\n\n?s Same as \"?B\".\n\n?x True if there is a next input file (that is, if the current input file is not the last\none).\n\nAny characters other than the special ones (question mark, colon, period, percent, and back‐\nslash) become literally part of the prompt. Any of the special characters may be included in\nthe prompt literally by preceding it with a backslash.\n\nSome examples:\n\n?f%f:Standard input.\n\nThis prompt prints the filename, if known; otherwise the string \"Standard input\".\n\n?f%f .?ltLine %lt:?pt%pt\\%:?btByte %bt:-...\n\nThis prompt would print the filename, if known. The filename is followed by the line number,\nif known, otherwise the percent if known, otherwise the byte offset if known. Otherwise, a\ndash is printed. Notice how each question mark has a matching period, and how the % after\nthe %pt is included literally by escaping it with a backslash.\n\n?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x..%t\";\n\nThis prints the filename if this is the first prompt in a file, followed by the \"file N of N\"\nmessage if there is more than one input file. Then, if we are at end-of-file, the string\n\"(END)\" is printed followed by the name of the next file, if there is one. Finally, any\ntrailing spaces are truncated. This is the default prompt. For reference, here are the de‐\nfaults for the other two prompts (-m and -M respectively). Each is broken into two lines\nhere for readability only.\n\n?n?f%f .?m(%T %i of %m) ..?e(END) ?x- Next\\: %x.:\n?pB%pB\\%:byte %bB?s/%s...%t\n\n?f%f .?n?m(%T %i of %m) ..?ltlines %lt-%lb?L/%L. :\nbyte %bB?s/%s. .?e(END) ?x- Next\\: %x.:?pB%pB\\%..%t\n\nAnd here is the default message produced by the = command:\n\n?f%f .?m(%T %i of %m) .?ltlines %lt-%lb?L/%L. .\nbyte %bB?s/%s. ?e(END) :?pB%pB\\%..%t\n\nThe prompt expansion features are also used for another purpose: if an environment variable\nLESSEDIT is defined, it is used as the command to be executed when the v command is invoked.\nThe LESSEDIT string is expanded in the same way as the prompt strings. The default value for\nLESSEDIT is:\n\n%E ?lm+%lm. %g\n\nNote that this expands to the editor name, followed by a + and the line number, followed by\nthe shell-escaped file name. If your editor does not accept the \"+linenumber\" syntax, or has\nother differences in invocation syntax, the LESSEDIT variable can be changed to modify this\ndefault.\n", "subsections": [] }, "SECURITY": { "content": "When the environment variable LESSSECURE is set to 1, less runs in a \"secure\" mode. This\nmeans these features are disabled:\n\n! the shell command\n\n| the pipe command\n\n:e the examine command.\n\nv the editing command\n\ns -o log files\n\n-k use of lesskey files\n\n-t use of tags files\n\nmetacharacters in filenames, such as *\n\nfilename completion (TAB, ^L)\n\nLess can also be compiled to be permanently in \"secure\" mode.\n", "subsections": [] }, "COMPATIBILITY WITH MORE": { "content": "If the environment variable LESSISMORE is set to 1, or if the program is invoked via a file\nlink named \"more\", less behaves (mostly) in conformance with the POSIX \"more\" command speci‐\nfication. In this mode, less behaves differently in these ways:\n\nThe -e option works differently. If the -e option is not set, less behaves as if the -e op‐\ntion were set. If the -e option is set, less behaves as if the -E option were set.\n\nThe -m option works differently. If the -m option is not set, the medium prompt is used, and\nit is prefixed with the string \"--More--\". If the -m option is set, the short prompt is\nused.\n\nThe -n option acts like the -z option. The normal behavior of the -n option is unavailable\nin this mode.\n\nThe parameter to the -p option is taken to be a less command rather than a search pattern.\n\nThe LESS environment variable is ignored, and the MORE environment variable is used in its\nplace.\n", "subsections": [] }, "ENVIRONMENT VARIABLES": { "content": "Environment variables may be specified either in the system environment as usual, or in a\nlesskey(1) file. If environment variables are defined in more than one place, variables de‐\nfined in a local lesskey file take precedence over variables defined in the system environ‐\nment, which take precedence over variables defined in the system-wide lesskey file.\n\nCOLUMNS\nSets the number of columns on the screen. Takes precedence over the number of columns\nspecified by the TERM variable. (But if you have a windowing system which supports\nTIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes precedence\nover the LINES and COLUMNS environment variables.)\n\nEDITOR The name of the editor (used for the v command).\n\nHOME Name of the user's home directory (used to find a lesskey file on Unix and OS/2 sys‐\ntems).\n\nHOMEDRIVE, HOMEPATH\nConcatenation of the HOMEDRIVE and HOMEPATH environment variables is the name of the\nuser's home directory if the HOME variable is not set (only in the Windows version).\n\nINIT Name of the user's init directory (used to find a lesskey file on OS/2 systems).\n\nLANG Language for determining the character set.\n\nLCCTYPE\nLanguage for determining the character set.\n\nLESS Options which are passed to less automatically.\n\nLESSANSIENDCHARS\nCharacters which may end an ANSI color escape sequence (default \"m\").\n\nLESSANSIMIDCHARS\nCharacters which may appear between the ESC character and the end character in an ANSI\ncolor escape sequence (default \"0123456789:;[?!\"'#%()*+ \".\n\nLESSBINFMT\nFormat for displaying non-printable, non-control characters.\n\nLESSCHARDEF\nDefines a character set.\n\nLESSCHARSET\nSelects a predefined character set.\n\nLESSCLOSE\nCommand line to invoke the (optional) input-postprocessor.\n\nLESSECHO\nName of the lessecho program (default \"lessecho\"). The lessecho program is needed to\nexpand metacharacters, such as * and ?, in filenames on Unix systems.\n\nLESSEDIT\nEditor prototype string (used for the v command). See discussion under PROMPTS.\n\nLESSGLOBALTAGS\nName of the command used by the -t option to find global tags. Normally should be set\nto \"global\" if your system has the global(1) command. If not set, global tags are not\nused.\n\nLESSHISTFILE\nName of the history file used to remember search commands and shell commands between\ninvocations of less. If set to \"-\" or \"/dev/null\", a history file is not used. The\ndefault is \"$XDGDATAHOME/lesshst\" or \"$HOME/.lesshst\" on Unix systems,\n\"$HOME/lesshst\" on DOS and Windows systems, or \"$HOME/lesshst.ini\" or\n\"$INIT/lesshst.ini\" on OS/2 systems.\n\nLESSHISTSIZE\nThe maximum number of commands to save in the history file. The default is 100.\n\nLESSKEYIN\nName of the default lesskey source file.\n\nLESSKEY\nName of the default lesskey binary file. (Not used if \"$LESSKEYIN\" exists.)\n\nLESSKEYINSYSTEM\nName of the default system-wide lesskey source file.\n\nLESSKEYSYSTEM\nName of the default system-wide lesskey binary file. (Not used if \"$LESSKEYINSYSTEM\"\nexists.)\n\nLESSMETACHARS\nList of characters which are considered \"metacharacters\" by the shell.\n\nLESSMETAESCAPE\nPrefix which less will add before each metacharacter in a command sent to the shell.\nIf LESSMETAESCAPE is an empty string, commands containing metacharacters will not be\npassed to the shell.\n\nLESSOPEN\nCommand line to invoke the (optional) input-preprocessor.\n\nLESSSECURE\nRuns less in \"secure\" mode. See discussion under SECURITY.\n\nLESSSEPARATOR\nString to be appended to a directory name in filename completion.\n\nLESSUTFBINFMT\nFormat for displaying non-printable Unicode code points.\n\nLESSISMORE\nEmulate the more(1) command.\n\nLINES Sets the number of lines on the screen. Takes precedence over the number of lines\nspecified by the TERM variable. (But if you have a windowing system which supports\nTIOCGWINSZ or WIOCGETD, the window system's idea of the screen size takes precedence\nover the LINES and COLUMNS environment variables.)\n\nMORE Options which are passed to less automatically when running in more compatible mode.\n\nPATH User's search path (used to find a lesskey file on MS-DOS and OS/2 systems).\n\nSHELL The shell used to execute the ! command, as well as to expand filenames.\n\nTERM The type of terminal on which less is being run.\n\nVISUAL The name of the editor (used for the v command).\n", "subsections": [] }, "SEE ALSO": { "content": "lesskey(1)\n", "subsections": [] }, "COPYRIGHT": { "content": "Copyright (C) 1984-2021 Mark Nudelman\n\nless is part of the GNU project and is free software. You can redistribute it and/or modify\nit under the terms of either (1) the GNU General Public License as published by the Free\nSoftware Foundation; or (2) the Less License. See the file README in the less distribution\nfor more details regarding redistribution. You should have received a copy of the GNU Gener‐\nal Public License along with the source for less; see the file COPYING. If not, write to the\nFree Software Foundation, 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA. You\nshould also have received a copy of the Less License; see the file LICENSE.\n\nless is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without\neven the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the\nGNU General Public License for more details.\n", "subsections": [] }, "AUTHOR": { "content": "Mark Nudelman\nReport bugs at https://github.com/gwsw/less/issues.\nFor more information, see the less homepage at\nhttps://greenwoodsoftware.com/less\n\n\n\nVersion 590: 03 Jun 2021 LESS(1)", "subsections": [] } }, "summary": "less - opposite of more", "flags": [ { "flag": "", "long": "--file-size", "arg": null, "description": "If --file-size is specified, less will determine the size of the file immediately af‐ ter opening the file. Normally this is not done, because it can be slow if the input file is large." }, { "flag": "", "long": "--follow-name", "arg": null, "description": "Normally, if the input file is renamed while an F command is executing, less will con‐ tinue to display the contents of the original file despite its name change. If --fol‐ low-name is specified, during an F command less will periodically attempt to reopen the file by name. If the reopen succeeds and the file is a different file from the original (which means that a new file has been created with the same name as the orig‐ inal (now renamed) file), less will display the contents of that new file." }, { "flag": "", "long": "--incsearch", "arg": null, "description": "Subsequent search commands will be \"incremental\"; that is, less will advance to the next line containing the search pattern as each character of the pattern is typed in." }, { "flag": "", "long": "--line-num-width", "arg": null, "description": "Sets the minimum width of the line number field when the -N option is in effect. The default is 7 characters." }, { "flag": "", "long": "--mouse", "arg": null, "description": "Enables mouse input: scrolling the mouse wheel down moves forward in the file, scrolling the mouse wheel up moves backwards in the file, and clicking the mouse sets the \"#\" mark to the line where the mouse is clicked. The number of lines to scroll when the wheel is moved can be set by the --wheel-lines option. Mouse input works on‐ ly on terminals which support X11 mouse reporting, and on the Windows version of less." }, { "flag": "", "long": "--MOUSE", "arg": null, "description": "Like --mouse, except the direction scrolled on mouse wheel movement is reversed." }, { "flag": "", "long": "--no-keypad", "arg": null, "description": "Disables sending the keypad initialization and deinitialization strings to the termi‐ nal. This is sometimes useful if the keypad strings make the numeric keypad behave in an undesirable manner." }, { "flag": "", "long": "--no-histdups", "arg": null, "description": "This option changes the behavior so that if a search string or file name is typed in, and the same string is already in the history list, the existing copy is removed from the history list before the new one is added. Thus, a given string will appear only once in the history list. Normally, a string may appear multiple times." }, { "flag": "", "long": "--rscroll", "arg": null, "description": "This option changes the character used to mark truncated lines. It may begin with a two-character attribute indicator like LESSBINFMT does. If there is no attribute in‐ dicator, standout is used. If set to \"-\", truncated lines are not marked." }, { "flag": "", "long": "--save-marks", "arg": null, "description": "Save marks in the history file, so marks are retained across different invocations of less." }, { "flag": "", "long": "--status-col-width", "arg": null, "description": "Sets the width of the status column when the -J option is in effect. The default is 2 characters." }, { "flag": "", "long": "--use-backslash", "arg": null, "description": "This option changes the interpretations of options which follow this one. After the --use-backslash option, any backslash in an option string is removed and the following character is taken literally. This allows a dollar sign to be included in option strings." }, { "flag": "", "long": "--use-color", "arg": null, "description": "Enables the colored text in various places. The -D option can be used to change the colors. Colored text works only if the terminal supports ANSI color escape sequences (as defined in ECMA-48 SGR; see https://www.ecma-international.org/publications-and-standards/standards/ecma-48). --wheel-lines=n Set the number of lines to scroll when the mouse wheel is scrolled and the --mouse or --MOUSE option is in effect. The default is 1 line. -- A command line argument of \"--\" marks the end of option arguments. Any arguments fol‐ lowing this are interpreted as filenames. This can be useful when viewing a file whose name begins with a \"-\" or \"+\". + If a command line option begins with +, the remainder of that option is taken to be an initial command to less. For example, +G tells less to start at the end of the file rather than the beginning, and +/xyz tells it to start at the first occurrence of \"xyz\" in the file. As a special case, + acts like +g; that is, it starts the display at the specified line number (however, see the caveat under the \"g\" command above). If the option starts with ++, the initial command applies to every file being viewed, not just the first one. The + command described previously may al‐ so be used to set (or change) an initial command for every file." } ], "examples": [], "see_also": [ { "name": "lesskey", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/lesskey/1/json" } ] }