{ "mode": "man", "parameter": "MAN", "section": "", "url": "https://www.chedong.com/phpMan.php/man/MAN/json", "generated": "2026-10-22T13:30:27Z", "synopsis": "man [man options] [[section] page ...] ...\nman -k [apropos options] regexp ...\nman -K [man options] [section] term ...\nman -f [whatis options] page ...\nman -l [man options] file ...\nman -w|-W [man options] page ...", "sections": { "NAME": { "content": "man - an interface to the system reference manuals\n", "subsections": [] }, "SYNOPSIS": { "content": "man [man options] [[section] page ...] ...\nman -k [apropos options] regexp ...\nman -K [man options] [section] term ...\nman -f [whatis options] page ...\nman -l [man options] file ...\nman -w|-W [man options] page ...\n", "subsections": [] }, "DESCRIPTION": { "content": "man is the system's manual pager. Each page argument given to man is normally the name of a\nprogram, utility or function. The manual page associated with each of these arguments is\nthen found and displayed. A section, if provided, will direct man to look only in that sec‐\ntion of the manual. The default action is to search in all of the available sections follow‐\ning a pre-defined order (see DEFAULTS), and to show only the first page found, even if page\nexists in several sections.\n\nThe table below shows the section numbers of the manual followed by the types of pages they\ncontain.\n\n1 Executable programs or shell commands\n2 System calls (functions provided by the kernel)\n3 Library calls (functions within program libraries)\n4 Special files (usually found in /dev)\n5 File formats and conventions, e.g. /etc/passwd\n6 Games\n7 Miscellaneous (including macro packages and conventions), e.g. man(7), groff(7),\nman-pages(7)\n8 System administration commands (usually only for root)\n9 Kernel routines [Non standard]\n\nA manual page consists of several sections.\n\nConventional section names include NAME, SYNOPSIS, CONFIGURATION, DESCRIPTION, OPTIONS,\nEXIT STATUS, RETURN VALUE, ERRORS, ENVIRONMENT, FILES, VERSIONS, STANDARDS, NOTES, BUGS, EX‐\nAMPLE, AUTHORS, and SEE ALSO.\n\nThe following conventions apply to the SYNOPSIS section and can be used as a guide in other\nsections.\n\nbold text type exactly as shown.\nitalic text replace with appropriate argument.\n[-abc] any or all arguments within [ ] are optional.", "subsections": [ { "name": "-a -b", "content": "argument ... argument is repeatable.\n[expression] ... entire expression within [ ] is repeatable.\n\nExact rendering may vary depending on the output device. For instance, man will usually not\nbe able to render italics when running in a terminal, and will typically use underlined or\ncoloured text instead.\n\nThe command or function illustration is a pattern that should match all possible invocations.\nIn some cases it is advisable to illustrate several exclusive invocations as is shown in the\nSYNOPSIS section of this manual page.\n", "flag": "-b" } ] }, "EXAMPLES": { "content": "man ls\nDisplay the manual page for the item (program) ls.\n\nman man.7\nDisplay the manual page for macro package man from section 7. (This is an alternative\nspelling of \"man 7 man\".)\n\nman 'man(7)'\nDisplay the manual page for macro package man from section 7. (This is another alterna‐\ntive spelling of \"man 7 man\". It may be more convenient when copying and pasting cross-\nreferences to manual pages. Note that the parentheses must normally be quoted to protect\nthem from the shell.)\n\nman -a intro\nDisplay, in succession, all of the available intro manual pages contained within the man‐\nual. It is possible to quit between successive displays or skip any of them.\n\nman -t bash | lpr -Pps\nFormat the manual page for bash into the default troff or groff format and pipe it to the\nprinter named ps. The default output for groff is usually PostScript. man --help should\nadvise as to which processor is bound to the -t option.\n\nman -l -Tdvi ./foo.1x.gz > ./foo.1x.dvi\nThis command will decompress and format the nroff source manual page ./foo.1x.gz into a\ndevice independent (dvi) file. The redirection is necessary as the -T flag causes output\nto be directed to stdout with no pager. The output could be viewed with a program such\nas xdvi or further processed into PostScript using a program such as dvips.\n\nman -k printf\nSearch the short descriptions and manual page names for the keyword printf as regular ex‐\npression. Print out any matches. Equivalent to apropos printf.\n\nman -f smail\nLookup the manual pages referenced by smail and print out the short descriptions of any\nfound. Equivalent to whatis smail.\n", "subsections": [] }, "OVERVIEW": { "content": "Many options are available to man in order to give as much flexibility as possible to the\nuser. Changes can be made to the search path, section order, output processor, and other be‐\nhaviours and operations detailed below.\n\nIf set, various environment variables are interrogated to determine the operation of man. It\nis possible to set the \"catch-all\" variable $MANOPT to any string in command line format,\nwith the exception that any spaces used as part of an option's argument must be escaped (pre‐\nceded by a backslash). man will parse $MANOPT prior to parsing its own command line. Those\noptions requiring an argument will be overridden by the same options found on the command\nline. To reset all of the options set in $MANOPT, -D can be specified as the initial command\nline option. This will allow man to \"forget\" about the options specified in $MANOPT, al‐\nthough they must still have been valid.\n\nManual pages are normally stored in nroff(1) format under a directory such as /usr/share/man.\nIn some installations, there may also be preformatted cat pages to improve performance. See\nmanpath(5) for details of where these files are stored.\n\nThis package supports manual pages in multiple languages, controlled by your locale. If your\nsystem did not set this up for you automatically, then you may need to set $LCMESSAGES,\n$LANG, or another system-dependent environment variable to indicate your preferred locale,\nusually specified in the POSIX format:\n\n[[.[,]]]\n\nIf the desired page is available in your locale, it will be displayed in lieu of the standard\n(usually American English) page.\n\nIf you find that the translations supplied with this package are not available in your native\nlanguage and you would like to supply them, please contact the maintainer who will be coordi‐\nnating such activity.\n\nIndividual manual pages are normally written and maintained by the maintainers of the pro‐\ngram, function, or other topic that they document, and are not included with this package.\nIf you find that a manual page is missing or inadequate, please report that to the maintain‐\ners of the package in question.\n\nFor information regarding other features and extensions available with this manual pager,\nplease read the documents supplied with the package.\n", "subsections": [] }, "DEFAULTS": { "content": "The order of sections to search may be overridden by the environment variable $MANSECT or by\nthe SECTION directive in /etc/manpath.config. By default it is as follows:\n\n1 n l 8 3 0 2 3type 3posix 3pm 3perl 3am 5 4 9 6 7\n\nThe formatted manual page is displayed using a pager. This can be specified in a number of\nways, or else will fall back to a default (see option -P for details).\n\nThe filters are deciphered by a number of means. Firstly, the command line option -p or the\nenvironment variable $MANROFFSEQ is interrogated. If -p was not used and the environment\nvariable was not set, the initial line of the nroff file is parsed for a preprocessor string.\nTo contain a valid preprocessor string, the first line must resemble\n\n'\\\" \n\nwhere string can be any combination of letters described by option -p below.\n\nIf none of the above methods provide any filter information, a default set is used.\n\nA formatting pipeline is formed from the filters and the primary formatter (nroff or [tg]roff\nwith -t) and executed. Alternatively, if an executable program mandbnfmt (or mandbtfmt\nwith -t) exists in the man tree root, it is executed instead. It gets passed the manual\nsource file, the preprocessor string, and optionally the device specified with -T or -E as\narguments.\n", "subsections": [] }, "OPTIONS": { "content": "Non-argument options that are duplicated either on the command line, in $MANOPT, or both, are\nnot harmful. For options that require an argument, each duplication will override the previ‐\nous argument value.\n", "subsections": [ { "name": "General options", "content": "" }, { "name": "-C _ --config-file=_", "content": "Use this user configuration file rather than the default of ~/.manpath.\n", "flag": "-C", "long": "--config-file", "arg": "_" }, { "name": "-d --debug", "content": "Print debugging information.\n", "flag": "-d", "long": "--debug" }, { "name": "-D --default", "content": "This option is normally issued as the very first option and resets man's behaviour to\nits default. Its use is to reset those options that may have been set in $MANOPT.\nAny options that follow -D will have their usual effect.\n\n--warnings[=warnings]\nEnable warnings from groff. This may be used to perform sanity checks on the source\ntext of manual pages. warnings is a comma-separated list of warning names; if it is\nnot supplied, the default is \"mac\". To disable a groff warning, prefix it with \"!\":\nfor example, --warnings=mac,!break enables warnings in the \"mac\" category and disables\nwarnings in the \"break\" category. See the “Warnings” node in info groff for a list of\navailable warning names.\n", "flag": "-D", "long": "--default" }, { "name": "Main modes of operation", "content": "" }, { "name": "-f --whatis", "content": "Approximately equivalent to whatis. Display a short description from the manual page,\nif available. See whatis(1) for details.\n", "flag": "-f", "long": "--whatis" }, { "name": "-k --apropos", "content": "Approximately equivalent to apropos. Search the short manual page descriptions for\nkeywords and display any matches. See apropos(1) for details.\n", "flag": "-k", "long": "--apropos" }, { "name": "-K --global-apropos", "content": "Search for text in all manual pages. This is a brute-force search, and is likely to\ntake some time; if you can, you should specify a section to reduce the number of pages\nthat need to be searched. Search terms may be simple strings (the default), or regu‐\nlar expressions if the --regex option is used.\n\nNote that this searches the sources of the manual pages, not the rendered text, and so\nmay include false positives due to things like comments in source files, or false neg‐\natives due to things like hyphens being written as \"\\-\" in source files. Searching\nthe rendered text would be much slower.\n", "flag": "-K", "long": "--global-apropos" }, { "name": "-l --local-file", "content": "Activate \"local\" mode. Format and display local manual files instead of searching\nthrough the system's manual collection. Each manual page argument will be interpreted\nas an nroff source file in the correct format. No cat file is produced. If '-' is\nlisted as one of the arguments, input will be taken from stdin.\n\nIf this option is not used, then man will also fall back to interpreting manual page\narguments as local file names if the argument contains a \"/\" character, since that is\na good indication that the argument refers to a path on the file system.\n", "flag": "-l", "long": "--local-file" }, { "name": "-w --where --path --location", "content": "Don't actually display the manual page, but do print the location of the source nroff\nfile that would be formatted. If the -a option is also used, then print the locations\nof all source files that match the search criteria.\n", "flag": "-w", "long": "--location" }, { "name": "-W --where-cat --location-cat", "content": "Don't actually display the manual page, but do print the location of the preformatted\ncat file that would be displayed. If the -a option is also used, then print the loca‐\ntions of all preformatted cat files that match the search criteria.\n\nIf -w and -W are both used, then print both source file and cat file separated by a\nspace. If all of -w, -W, and -a are used, then do this for each possible match.\n", "flag": "-W", "long": "--location-cat" }, { "name": "-c --catman", "content": "This option is not for general use and should only be used by the catman program.\n", "flag": "-c", "long": "--catman" }, { "name": "-R _ --recode", "content": "Instead of formatting the manual page in the usual way, output its source converted to\nthe specified encoding. If you already know the encoding of the source file, you can\nalso use manconv(1) directly. However, this option allows you to convert several man‐\nual pages to a single encoding without having to explicitly state the encoding of\neach, provided that they were already installed in a structure similar to a manual\npage hierarchy.\n\nConsider using man-recode(1) instead for converting multiple manual pages, since it\nhas an interface designed for bulk conversion and so can be much faster.\n", "flag": "-R", "long": "--recode" }, { "name": "Finding manual pages", "content": "" }, { "name": "-L _ --locale=_", "content": "man will normally determine your current locale by a call to the C function setlo‐\ncale(3) which interrogates various environment variables, possibly including $LCMES‐\nSAGES and $LANG. To temporarily override the determined value, use this option to\nsupply a locale string directly to man. Note that it will not take effect until the\nsearch for pages actually begins. Output such as the help message will always be dis‐\nplayed in the initially determined locale.\n", "flag": "-L", "long": "--locale", "arg": "_" }, { "name": "-m _ --systems=_", "content": "If this system has access to other operating systems' manual pages, they can be ac‐\ncessed using this option. To search for a manual page from NewOS's manual page col‐\nlection, use the option -m NewOS.\n\nThe system specified can be a combination of comma delimited operating system names.\nTo include a search of the native operating system's manual pages, include the system\nname man in the argument string. This option will override the $SYSTEM environment\nvariable.\n", "flag": "-m", "long": "--systems", "arg": "_" }, { "name": "-M _ --manpath=_", "content": "Specify an alternate manpath to use. By default, man uses manpath derived code to de‐\ntermine the path to search. This option overrides the $MANPATH environment variable\nand causes option -m to be ignored.\n\nA path specified as a manpath must be the root of a manual page hierarchy structured\ninto sections as described in the man-db manual (under \"The manual page system\"). To\nview manual pages outside such hierarchies, see the -l option.\n", "flag": "-M", "long": "--manpath", "arg": "_" }, { "name": "-S _ -s _ --sections=_", "content": "The given list is a colon- or comma-separated list of sections, used to determine\nwhich manual sections to search and in what order. This option overrides the $MANSECT\nenvironment variable. (The -s spelling is for compatibility with System V.)\n", "flag": "-s", "long": "--sections", "arg": "_" }, { "name": "-e _ --extension=_", "content": "Some systems incorporate large packages of manual pages, such as those that accompany\nthe Tcl package, into the main manual page hierarchy. To get around the problem of\nhaving two manual pages with the same name such as exit(3), the Tcl pages were usually\nall assigned to section l. As this is unfortunate, it is now possible to put the\npages in the correct section, and to assign a specific \"extension\" to them, in this\ncase, exit(3tcl). Under normal operation, man will display exit(3) in preference to\nexit(3tcl). To negotiate this situation and to avoid having to know which section the\npage you require resides in, it is now possible to give man a sub-extension string in‐\ndicating which package the page must belong to. Using the above example, supplying\nthe option -e tcl to man will restrict the search to pages having an extension of\n*tcl.\n", "flag": "-e", "long": "--extension", "arg": "_" }, { "name": "-i --ignore-case", "content": "Ignore case when searching for manual pages. This is the default.\n", "flag": "-i", "long": "--ignore-case" }, { "name": "-I --match-case", "content": "Search for manual pages case-sensitively.\n", "flag": "-I", "long": "--match-case" }, { "name": "--regex", "content": "Show all pages with any part of either their names or their descriptions matching each\npage argument as a regular expression, as with apropos(1). Since there is usually no\nreasonable way to pick a \"best\" page when searching for a regular expression, this op‐\ntion implies -a.\n", "long": "--regex" }, { "name": "--wildcard", "content": "Show all pages with any part of either their names or their descriptions matching each\npage argument using shell-style wildcards, as with apropos(1) --wildcard. The page\nargument must match the entire name or description, or match on word boundaries in the\ndescription. Since there is usually no reasonable way to pick a \"best\" page when\nsearching for a wildcard, this option implies -a.\n", "long": "--wildcard" }, { "name": "--names-only", "content": "If the --regex or --wildcard option is used, match only page names, not page descrip‐\ntions, as with whatis(1). Otherwise, no effect.\n", "long": "--names-only" }, { "name": "-a --all", "content": "By default, man will exit after displaying the most suitable manual page it finds.\nUsing this option forces man to display all the manual pages with names that match the\nsearch criteria.\n", "flag": "-a", "long": "--all" }, { "name": "-u --update", "content": "This option causes man to update its database caches of installed manual pages. This\nis only needed in rare situations, and it is normally better to run mandb(8) instead.\n", "flag": "-u", "long": "--update" }, { "name": "--no-subpages", "content": "By default, man will try to interpret pairs of manual page names given on the command\nline as equivalent to a single manual page name containing a hyphen or an underscore.\nThis supports the common pattern of programs that implement a number of subcommands,\nallowing them to provide manual pages for each that can be accessed using similar syn‐\ntax as would be used to invoke the subcommands themselves. For example:\n\n$ man -aw git diff\n/usr/share/man/man1/git-diff.1.gz\n\nTo disable this behaviour, use the --no-subpages option.\n\n$ man -aw --no-subpages git diff\n/usr/share/man/man1/git.1.gz\n/usr/share/man/man3/Git.3pm.gz\n/usr/share/man/man1/diff.1.gz\n", "long": "--no-subpages" }, { "name": "Controlling formatted output", "content": "" }, { "name": "-P _ --pager=_", "content": "Specify which output pager to use. By default, man uses pager, falling back to cat if\npager is not found or is not executable. This option overrides the $MANPAGER environ‐\nment variable, which in turn overrides the $PAGER environment variable. It is not\nused in conjunction with -f or -k.\n\nThe value may be a simple command name or a command with arguments, and may use shell\nquoting (backslashes, single quotes, or double quotes). It may not use pipes to con‐\nnect multiple commands; if you need that, use a wrapper script, which may take the\nfile to display either as an argument or on standard input.\n", "flag": "-P", "long": "--pager", "arg": "_" }, { "name": "-r _ --prompt=_", "content": "If a recent version of less is used as the pager, man will attempt to set its prompt\nand some sensible options. The default prompt looks like\n\nManual page name(sec) line x\n\nwhere name denotes the manual page name, sec denotes the section it was found under\nand x the current line number. This is achieved by using the $LESS environment vari‐\nable.\n\nSupplying -r with a string will override this default. The string may contain the\ntext $MANPN which will be expanded to the name of the current manual page and its\nsection name surrounded by \"(\" and \")\". The string used to produce the default could\nbe expressed as\n\n\\ Manual\\ page\\ \\$MANPN\\ ?ltline\\ %lt?L/%L.:\nbyte\\ %bB?s/%s..?\\ (END):?pB\\ %pB\\\\%..\n(press h for help or q to quit)\n\nIt is broken into three lines here for the sake of readability only. For its meaning\nsee the less(1) manual page. The prompt string is first evaluated by the shell. All\ndouble quotes, back-quotes and backslashes in the prompt must be escaped by a preced‐\ning backslash. The prompt string may end in an escaped $ which may be followed by\nfurther options for less. By default man sets the -ix8 options.\n\nThe $MANLESS environment variable described below may be used to set a default prompt\nstring if none is supplied on the command line.\n", "flag": "-r", "long": "--prompt", "arg": "_" }, { "name": "-7 --ascii", "content": "When viewing a pure ascii(7) manual page on a 7 bit terminal or terminal emulator,\nsome characters may not display correctly when using the latin1(7) device description\nwith GNU nroff. This option allows pure ascii manual pages to be displayed in ascii\nwith the latin1 device. It will not translate any latin1 text. The following table\nshows the translations performed: some parts of it may only be displayed properly when\nusing GNU nroff's latin1(7) device.\n\nDescription Octal latin1 ascii\n─────────────────────────────────────────────\ncontinuation hyphen 255 ‐ -\nbullet (middle dot) 267 • o\nacute accent 264 ´ '\nmultiplication sign 327 × x\n\nIf the latin1 column displays correctly, your terminal may be set up for latin1 char‐\nacters and this option is not necessary. If the latin1 and ascii columns are identi‐\ncal, you are reading this page using this option or man did not format this page using\nthe latin1 device description. If the latin1 column is missing or corrupt, you may\nneed to view manual pages with this option.\n\nThis option is ignored when using options -t, -H, -T, or -Z and may be useless for\nnroff other than GNU's.\n", "flag": "-7", "long": "--ascii" }, { "name": "-E _ --encoding", "content": "Generate output for a character encoding other than the default. For backward compat‐\nibility, encoding may be an nroff device such as ascii, latin1, or utf8 as well as a\ntrue character encoding such as UTF-8.\n\n--no-hyphenation, --nh\nNormally, nroff will automatically hyphenate text at line breaks even in words that do\nnot contain hyphens, if it is necessary to do so to lay out words on a line without\nexcessive spacing. This option disables automatic hyphenation, so words will only be\nhyphenated if they already contain hyphens.\n\nIf you are writing a manual page and simply want to prevent nroff from hyphenating a\nword at an inappropriate point, do not use this option, but consult the nroff documen‐\ntation instead; for instance, you can put \"\\%\" inside a word to indicate that it may\nbe hyphenated at that point, or put \"\\%\" at the start of a word to prevent it from be‐\ning hyphenated.\n\n--no-justification, --nj\nNormally, nroff will automatically justify text to both margins. This option disables\nfull justification, leaving justified only to the left margin, sometimes called\n\"ragged-right\" text.\n\nIf you are writing a manual page and simply want to prevent nroff from justifying cer‐\ntain paragraphs, do not use this option, but consult the nroff documentation instead;\nfor instance, you can use the \".na\", \".nf\", \".fi\", and \".ad\" requests to temporarily\ndisable adjusting and filling.\n", "flag": "-E", "long": "--encoding" }, { "name": "-p _ --preprocessor=_", "content": "Specify the sequence of preprocessors to run before nroff or troff/groff. Not all in‐\nstallations will have a full set of preprocessors. Some of the preprocessors and the\nletters used to designate them are: eqn (e), grap (g), pic (p), tbl (t), vgrind (v),\nrefer (r). This option overrides the $MANROFFSEQ environment variable. zsoelim is\nalways run as the very first preprocessor.\n", "flag": "-p", "long": "--preprocessor", "arg": "_" }, { "name": "-t --troff", "content": "Use groff -mandoc to format the manual page to stdout. This option is not required in\nconjunction with -H, -T, or -Z.\n", "flag": "-t", "long": "--troff" }, { "name": "-T --troff-device", "content": "This option is used to change groff (or possibly troff's) output to be suitable for a\ndevice other than the default. It implies -t. Examples (provided with Groff-1.17)\ninclude dvi, latin1, ps, utf8, X75 and X100.\n", "flag": "-T", "long": "--troff-device" }, { "name": "-H --html", "content": "This option will cause groff to produce HTML output, and will display that output in a\nweb browser. The choice of browser is determined by the optional browser argument if\none is provided, by the $BROWSER environment variable, or by a compile-time default if\nthat is unset (usually lynx). This option implies -t, and will only work with GNU\ntroff.\n", "flag": "-H", "long": "--html" }, { "name": "-X --gxditview", "content": "This option displays the output of groff in a graphical window using the gxditview\nprogram. The dpi (dots per inch) may be 75, 75-12, 100, or 100-12, defaulting to 75;\nthe -12 variants use a 12-point base font. This option implies -T with the X75,\nX75-12, X100, or X100-12 device respectively.\n", "flag": "-X", "long": "--gxditview" }, { "name": "-Z --ditroff", "content": "groff will run troff and then use an appropriate post-processor to produce output\nsuitable for the chosen device. If groff -mandoc is groff, this option is passed to\ngroff and will suppress the use of a post-processor. It implies -t.\n", "flag": "-Z", "long": "--ditroff" }, { "name": "Getting help", "content": "-?, --help\nPrint a help message and exit.\n" }, { "name": "--usage", "content": "Print a short usage message and exit.\n", "long": "--usage" }, { "name": "-V --version", "content": "Display version information.\n", "flag": "-V", "long": "--version" } ] }, "EXIT STATUS": { "content": "0 Successful program execution.\n\n1 Usage, syntax or configuration file error.\n\n2 Operational error.\n\n3 A child process returned a non-zero exit status.\n\n16 At least one of the pages/files/keywords didn't exist or wasn't matched.\n", "subsections": [] }, "ENVIRONMENT": { "content": "MANPATH\nIf $MANPATH is set, its value is used as the path to search for manual pages.\n\nSee the SEARCH PATH section of manpath(5) for the default behaviour and details of how\nthis environment variable is handled.\n\nMANROFFOPT\nEvery time man invokes the formatter (nroff, troff, or groff), it adds the contents of\n$MANROFFOPT to the formatter's command line.\n\nMANROFFSEQ\nIf $MANROFFSEQ is set, its value is used to determine the set of preprocessors to pass\neach manual page through. The default preprocessor list is system dependent.\n\nMANSECT\nIf $MANSECT is set, its value is a colon-delimited list of sections and it is used to\ndetermine which manual sections to search and in what order. The default is \"1 n l 8\n3 0 2 3type 3posix 3pm 3perl 3am 5 4 9 6 7\", unless overridden by the SECTION direc‐\ntive in /etc/manpath.config.\n\nMANPAGER, PAGER\nIf $MANPAGER or $PAGER is set ($MANPAGER is used in preference), its value is used as\nthe name of the program used to display the manual page. By default, pager is used,\nfalling back to cat if pager is not found or is not executable.\n\nThe value may be a simple command name or a command with arguments, and may use shell\nquoting (backslashes, single quotes, or double quotes). It may not use pipes to con‐\nnect multiple commands; if you need that, use a wrapper script, which may take the\nfile to display either as an argument or on standard input.\n\nMANLESS\nIf $MANLESS is set, its value will be used as the default prompt string for the less\npager, as if it had been passed using the -r option (so any occurrences of the text\n$MANPN will be expanded in the same way). For example, if you want to set the prompt\nstring unconditionally to “my prompt string”, set $MANLESS to ‘-Psmy prompt string’.\nUsing the -r option overrides this environment variable.\n\nBROWSER\nIf $BROWSER is set, its value is a colon-delimited list of commands, each of which in\nturn is used to try to start a web browser for man --html. In each command, %s is re‐\nplaced by a filename containing the HTML output from groff, %% is replaced by a single\npercent sign (%), and %c is replaced by a colon (:).\n\nSYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the ar‐\ngument to the -m option.\n\nMANOPT If $MANOPT is set, it will be parsed prior to man's command line and is expected to be\nin a similar format. As all of the other man specific environment variables can be\nexpressed as command line options, and are thus candidates for being included in\n$MANOPT it is expected that they will become obsolete. N.B. All spaces that should\nbe interpreted as part of an option's argument must be escaped.\n\nMANWIDTH\nIf $MANWIDTH is set, its value is used as the line length for which manual pages\nshould be formatted. If it is not set, manual pages will be formatted with a line\nlength appropriate to the current terminal (using the value of $COLUMNS, and ioctl(2)\nif available, or falling back to 80 characters if neither is available). Cat pages\nwill only be saved when the default formatting can be used, that is when the terminal\nline length is between 66 and 80 characters.\n\nMANKEEPFORMATTING\nNormally, when output is not being directed to a terminal (such as to a file or a\npipe), formatting characters are discarded to make it easier to read the result with‐\nout special tools. However, if $MANKEEPFORMATTING is set to any non-empty value,\nthese formatting characters are retained. This may be useful for wrappers around man\nthat can interpret formatting characters.\n\nMANKEEPSTDERR\nNormally, when output is being directed to a terminal (usually to a pager), any error\noutput from the command used to produce formatted versions of manual pages is dis‐\ncarded to avoid interfering with the pager's display. Programs such as groff often\nproduce relatively minor error messages about typographical problems such as poor\nalignment, which are unsightly and generally confusing when displayed along with the\nmanual page. However, some users want to see them anyway, so, if $MANKEEPSTDERR is\nset to any non-empty value, error output will be displayed as usual.\n\nMANDISABLESECCOMP\nOn Linux, man normally confines subprocesses that handle untrusted data using a sec‐\ncomp(2) sandbox. This makes it safer to run complex parsing code over arbitrary man‐\nual pages. If this goes wrong for some reason unrelated to the content of the page\nbeing displayed, you can set $MANDISABLESECCOMP to any non-empty value to disable\nthe sandbox.\n\nPIPELINEDEBUG\nIf the $PIPELINEDEBUG environment variable is set to \"1\", then man will print debug‐\nging messages to standard error describing each subprocess it runs.\n\nLANG, LCMESSAGES\nDepending on system and implementation, either or both of $LANG and $LCMESSAGES will\nbe interrogated for the current message locale. man will display its messages in that\nlocale (if available). See setlocale(3) for precise details.\n", "subsections": [] }, "FILES": { "content": "/etc/manpath.config\nman-db configuration file.\n\n/usr/share/man\nA global manual page hierarchy.\n", "subsections": [] }, "STANDARDS": { "content": "POSIX.1-2001, POSIX.1-2008, POSIX.1-2017.\n", "subsections": [] }, "SEE ALSO": { "content": "apropos(1), groff(1), less(1), manpath(1), nroff(1), troff(1), whatis(1), zsoelim(1), man‐\npath(5), man(7), catman(8), mandb(8)\n\nDocumentation for some packages may be available in other formats, such as info(1) or HTML.\n", "subsections": [] }, "HISTORY": { "content": "1990, 1991 – Originally written by John W. Eaton (jwe@che.utexas.edu).\n\nDec 23 1992: Rik Faith (faith@cs.unc.edu) applied bug fixes supplied by Willem Kasdorp\n(wkasdo@nikhefk.nikef.nl).\n\n30th April 1994 – 23rd February 2000: Wilf. (G.Wilford@ee.surrey.ac.uk) has been developing\nand maintaining this package with the help of a few dedicated people.\n\n30th October 1996 – 30th March 2001: Fabrizio Polacco maintained and\nenhanced this package for the Debian project, with the help of all the community.\n\n31st March 2001 – present day: Colin Watson is now developing and main‐\ntaining man-db.\n", "subsections": [] }, "BUGS": { "content": "https://gitlab.com/man-db/man-db/-/issues\nhttps://savannah.nongnu.org/bugs/?group=man-db\n\n2.12.0 2023-09-23 MAN(1)", "subsections": [] } }, "summary": "man - an interface to the system reference manuals", "flags": [ { "flag": "-C", "long": "--config-file", "arg": "_", "description": "Use this user configuration file rather than the default of ~/.manpath." }, { "flag": "-d", "long": "--debug", "arg": null, "description": "Print debugging information." }, { "flag": "-D", "long": "--default", "arg": null, "description": "This option is normally issued as the very first option and resets man's behaviour to its default. Its use is to reset those options that may have been set in $MANOPT. Any options that follow -D will have their usual effect. --warnings[=warnings] Enable warnings from groff. This may be used to perform sanity checks on the source text of manual pages. warnings is a comma-separated list of warning names; if it is not supplied, the default is \"mac\". To disable a groff warning, prefix it with \"!\": for example, --warnings=mac,!break enables warnings in the \"mac\" category and disables warnings in the \"break\" category. See the “Warnings” node in info groff for a list of available warning names." }, { "flag": "-f", "long": "--whatis", "arg": null, "description": "Approximately equivalent to whatis. Display a short description from the manual page, if available. See whatis(1) for details." }, { "flag": "-k", "long": "--apropos", "arg": null, "description": "Approximately equivalent to apropos. Search the short manual page descriptions for keywords and display any matches. See apropos(1) for details." }, { "flag": "-K", "long": "--global-apropos", "arg": null, "description": "Search for text in all manual pages. This is a brute-force search, and is likely to take some time; if you can, you should specify a section to reduce the number of pages that need to be searched. Search terms may be simple strings (the default), or regu‐ lar expressions if the --regex option is used. Note that this searches the sources of the manual pages, not the rendered text, and so may include false positives due to things like comments in source files, or false neg‐ atives due to things like hyphens being written as \"\\-\" in source files. Searching the rendered text would be much slower." }, { "flag": "-l", "long": "--local-file", "arg": null, "description": "Activate \"local\" mode. Format and display local manual files instead of searching through the system's manual collection. Each manual page argument will be interpreted as an nroff source file in the correct format. No cat file is produced. If '-' is listed as one of the arguments, input will be taken from stdin. If this option is not used, then man will also fall back to interpreting manual page arguments as local file names if the argument contains a \"/\" character, since that is a good indication that the argument refers to a path on the file system." }, { "flag": "-w", "long": "--location", "arg": null, "description": "Don't actually display the manual page, but do print the location of the source nroff file that would be formatted. If the -a option is also used, then print the locations of all source files that match the search criteria." }, { "flag": "-W", "long": "--location-cat", "arg": null, "description": "Don't actually display the manual page, but do print the location of the preformatted cat file that would be displayed. If the -a option is also used, then print the loca‐ tions of all preformatted cat files that match the search criteria. If -w and -W are both used, then print both source file and cat file separated by a space. If all of -w, -W, and -a are used, then do this for each possible match." }, { "flag": "-c", "long": "--catman", "arg": null, "description": "This option is not for general use and should only be used by the catman program." }, { "flag": "-R", "long": "--recode", "arg": null, "description": "Instead of formatting the manual page in the usual way, output its source converted to the specified encoding. If you already know the encoding of the source file, you can also use manconv(1) directly. However, this option allows you to convert several man‐ ual pages to a single encoding without having to explicitly state the encoding of each, provided that they were already installed in a structure similar to a manual page hierarchy. Consider using man-recode(1) instead for converting multiple manual pages, since it has an interface designed for bulk conversion and so can be much faster." }, { "flag": "-L", "long": "--locale", "arg": "_", "description": "man will normally determine your current locale by a call to the C function setlo‐ cale(3) which interrogates various environment variables, possibly including $LCMES‐ SAGES and $LANG. To temporarily override the determined value, use this option to supply a locale string directly to man. Note that it will not take effect until the search for pages actually begins. Output such as the help message will always be dis‐ played in the initially determined locale." }, { "flag": "-m", "long": "--systems", "arg": "_", "description": "If this system has access to other operating systems' manual pages, they can be ac‐ cessed using this option. To search for a manual page from NewOS's manual page col‐ lection, use the option -m NewOS. The system specified can be a combination of comma delimited operating system names. To include a search of the native operating system's manual pages, include the system name man in the argument string. This option will override the $SYSTEM environment variable." }, { "flag": "-M", "long": "--manpath", "arg": "_", "description": "Specify an alternate manpath to use. By default, man uses manpath derived code to de‐ termine the path to search. This option overrides the $MANPATH environment variable and causes option -m to be ignored. A path specified as a manpath must be the root of a manual page hierarchy structured into sections as described in the man-db manual (under \"The manual page system\"). To view manual pages outside such hierarchies, see the -l option." }, { "flag": "-s", "long": "--sections", "arg": "_", "description": "The given list is a colon- or comma-separated list of sections, used to determine which manual sections to search and in what order. This option overrides the $MANSECT environment variable. (The -s spelling is for compatibility with System V.)" }, { "flag": "-e", "long": "--extension", "arg": "_", "description": "Some systems incorporate large packages of manual pages, such as those that accompany the Tcl package, into the main manual page hierarchy. To get around the problem of having two manual pages with the same name such as exit(3), the Tcl pages were usually all assigned to section l. As this is unfortunate, it is now possible to put the pages in the correct section, and to assign a specific \"extension\" to them, in this case, exit(3tcl). Under normal operation, man will display exit(3) in preference to exit(3tcl). To negotiate this situation and to avoid having to know which section the page you require resides in, it is now possible to give man a sub-extension string in‐ dicating which package the page must belong to. Using the above example, supplying the option -e tcl to man will restrict the search to pages having an extension of *tcl." }, { "flag": "-i", "long": "--ignore-case", "arg": null, "description": "Ignore case when searching for manual pages. This is the default." }, { "flag": "-I", "long": "--match-case", "arg": null, "description": "Search for manual pages case-sensitively." }, { "flag": "", "long": "--regex", "arg": null, "description": "Show all pages with any part of either their names or their descriptions matching each page argument as a regular expression, as with apropos(1). Since there is usually no reasonable way to pick a \"best\" page when searching for a regular expression, this op‐ tion implies -a." }, { "flag": "", "long": "--wildcard", "arg": null, "description": "Show all pages with any part of either their names or their descriptions matching each page argument using shell-style wildcards, as with apropos(1) --wildcard. The page argument must match the entire name or description, or match on word boundaries in the description. Since there is usually no reasonable way to pick a \"best\" page when searching for a wildcard, this option implies -a." }, { "flag": "", "long": "--names-only", "arg": null, "description": "If the --regex or --wildcard option is used, match only page names, not page descrip‐ tions, as with whatis(1). Otherwise, no effect." }, { "flag": "-a", "long": "--all", "arg": null, "description": "By default, man will exit after displaying the most suitable manual page it finds. Using this option forces man to display all the manual pages with names that match the search criteria." }, { "flag": "-u", "long": "--update", "arg": null, "description": "This option causes man to update its database caches of installed manual pages. This is only needed in rare situations, and it is normally better to run mandb(8) instead." }, { "flag": "", "long": "--no-subpages", "arg": null, "description": "By default, man will try to interpret pairs of manual page names given on the command line as equivalent to a single manual page name containing a hyphen or an underscore. This supports the common pattern of programs that implement a number of subcommands, allowing them to provide manual pages for each that can be accessed using similar syn‐ tax as would be used to invoke the subcommands themselves. For example: $ man -aw git diff /usr/share/man/man1/git-diff.1.gz To disable this behaviour, use the --no-subpages option. $ man -aw --no-subpages git diff /usr/share/man/man1/git.1.gz /usr/share/man/man3/Git.3pm.gz /usr/share/man/man1/diff.1.gz" }, { "flag": "-P", "long": "--pager", "arg": "_", "description": "Specify which output pager to use. By default, man uses pager, falling back to cat if pager is not found or is not executable. This option overrides the $MANPAGER environ‐ ment variable, which in turn overrides the $PAGER environment variable. It is not used in conjunction with -f or -k. The value may be a simple command name or a command with arguments, and may use shell quoting (backslashes, single quotes, or double quotes). It may not use pipes to con‐ nect multiple commands; if you need that, use a wrapper script, which may take the file to display either as an argument or on standard input." }, { "flag": "-r", "long": "--prompt", "arg": "_", "description": "If a recent version of less is used as the pager, man will attempt to set its prompt and some sensible options. The default prompt looks like Manual page name(sec) line x where name denotes the manual page name, sec denotes the section it was found under and x the current line number. This is achieved by using the $LESS environment vari‐ able. Supplying -r with a string will override this default. The string may contain the text $MANPN which will be expanded to the name of the current manual page and its section name surrounded by \"(\" and \")\". The string used to produce the default could be expressed as \\ Manual\\ page\\ \\$MANPN\\ ?ltline\\ %lt?L/%L.: byte\\ %bB?s/%s..?\\ (END):?pB\\ %pB\\\\%.. (press h for help or q to quit) It is broken into three lines here for the sake of readability only. For its meaning see the less(1) manual page. The prompt string is first evaluated by the shell. All double quotes, back-quotes and backslashes in the prompt must be escaped by a preced‐ ing backslash. The prompt string may end in an escaped $ which may be followed by further options for less. By default man sets the -ix8 options. The $MANLESS environment variable described below may be used to set a default prompt string if none is supplied on the command line." }, { "flag": "-7", "long": "--ascii", "arg": null, "description": "When viewing a pure ascii(7) manual page on a 7 bit terminal or terminal emulator, some characters may not display correctly when using the latin1(7) device description with GNU nroff. This option allows pure ascii manual pages to be displayed in ascii with the latin1 device. It will not translate any latin1 text. The following table shows the translations performed: some parts of it may only be displayed properly when using GNU nroff's latin1(7) device. Description Octal latin1 ascii ───────────────────────────────────────────── continuation hyphen 255 ‐ - bullet (middle dot) 267 • o acute accent 264 ´ ' multiplication sign 327 × x If the latin1 column displays correctly, your terminal may be set up for latin1 char‐ acters and this option is not necessary. If the latin1 and ascii columns are identi‐ cal, you are reading this page using this option or man did not format this page using the latin1 device description. If the latin1 column is missing or corrupt, you may need to view manual pages with this option. This option is ignored when using options -t, -H, -T, or -Z and may be useless for nroff other than GNU's." }, { "flag": "-E", "long": "--encoding", "arg": null, "description": "Generate output for a character encoding other than the default. For backward compat‐ ibility, encoding may be an nroff device such as ascii, latin1, or utf8 as well as a true character encoding such as UTF-8. --no-hyphenation, --nh Normally, nroff will automatically hyphenate text at line breaks even in words that do not contain hyphens, if it is necessary to do so to lay out words on a line without excessive spacing. This option disables automatic hyphenation, so words will only be hyphenated if they already contain hyphens. If you are writing a manual page and simply want to prevent nroff from hyphenating a word at an inappropriate point, do not use this option, but consult the nroff documen‐ tation instead; for instance, you can put \"\\%\" inside a word to indicate that it may be hyphenated at that point, or put \"\\%\" at the start of a word to prevent it from be‐ ing hyphenated. --no-justification, --nj Normally, nroff will automatically justify text to both margins. This option disables full justification, leaving justified only to the left margin, sometimes called \"ragged-right\" text. If you are writing a manual page and simply want to prevent nroff from justifying cer‐ tain paragraphs, do not use this option, but consult the nroff documentation instead; for instance, you can use the \".na\", \".nf\", \".fi\", and \".ad\" requests to temporarily disable adjusting and filling." }, { "flag": "-p", "long": "--preprocessor", "arg": "_", "description": "Specify the sequence of preprocessors to run before nroff or troff/groff. Not all in‐ stallations will have a full set of preprocessors. Some of the preprocessors and the letters used to designate them are: eqn (e), grap (g), pic (p), tbl (t), vgrind (v), refer (r). This option overrides the $MANROFFSEQ environment variable. zsoelim is always run as the very first preprocessor." }, { "flag": "-t", "long": "--troff", "arg": null, "description": "Use groff -mandoc to format the manual page to stdout. This option is not required in conjunction with -H, -T, or -Z." }, { "flag": "-T", "long": "--troff-device", "arg": null, "description": "This option is used to change groff (or possibly troff's) output to be suitable for a device other than the default. It implies -t. Examples (provided with Groff-1.17) include dvi, latin1, ps, utf8, X75 and X100." }, { "flag": "-H", "long": "--html", "arg": null, "description": "This option will cause groff to produce HTML output, and will display that output in a web browser. The choice of browser is determined by the optional browser argument if one is provided, by the $BROWSER environment variable, or by a compile-time default if that is unset (usually lynx). This option implies -t, and will only work with GNU troff." }, { "flag": "-X", "long": "--gxditview", "arg": null, "description": "This option displays the output of groff in a graphical window using the gxditview program. The dpi (dots per inch) may be 75, 75-12, 100, or 100-12, defaulting to 75; the -12 variants use a 12-point base font. This option implies -T with the X75, X75-12, X100, or X100-12 device respectively." }, { "flag": "-Z", "long": "--ditroff", "arg": null, "description": "groff will run troff and then use an appropriate post-processor to produce output suitable for the chosen device. If groff -mandoc is groff, this option is passed to groff and will suppress the use of a post-processor. It implies -t." }, { "flag": "", "long": "--usage", "arg": null, "description": "Print a short usage message and exit." }, { "flag": "-V", "long": "--version", "arg": null, "description": "Display version information." } ], "examples": [ "man ls", "Display the manual page for the item (program) ls.", "man man.7", "Display the manual page for macro package man from section 7. (This is an alternative", "spelling of \"man 7 man\".)", "man 'man(7)'", "Display the manual page for macro package man from section 7. (This is another alterna‐", "tive spelling of \"man 7 man\". It may be more convenient when copying and pasting cross-", "references to manual pages. Note that the parentheses must normally be quoted to protect", "them from the shell.)", "man -a intro", "Display, in succession, all of the available intro manual pages contained within the man‐", "ual. It is possible to quit between successive displays or skip any of them.", "man -t bash | lpr -Pps", "Format the manual page for bash into the default troff or groff format and pipe it to the", "printer named ps. The default output for groff is usually PostScript. man --help should", "advise as to which processor is bound to the -t option.", "man -l -Tdvi ./foo.1x.gz > ./foo.1x.dvi", "This command will decompress and format the nroff source manual page ./foo.1x.gz into a", "device independent (dvi) file. The redirection is necessary as the -T flag causes output", "to be directed to stdout with no pager. The output could be viewed with a program such", "as xdvi or further processed into PostScript using a program such as dvips.", "man -k printf", "Search the short descriptions and manual page names for the keyword printf as regular ex‐", "pression. Print out any matches. Equivalent to apropos printf.", "man -f smail", "Lookup the manual pages referenced by smail and print out the short descriptions of any", "found. Equivalent to whatis smail." ], "see_also": [ { "name": "apropos", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/apropos/1/json" }, { "name": "groff", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/groff/1/json" }, { "name": "less", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/less/1/json" }, { "name": "manpath", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/manpath/1/json" }, { "name": "nroff", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/nroff/1/json" }, { "name": "troff", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/troff/1/json" }, { "name": "whatis", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/whatis/1/json" }, { "name": "zsoelim", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/zsoelim/1/json" }, { "name": "path", "section": "5", "url": "https://www.chedong.com/phpMan.php/man/path/5/json" }, { "name": "man", "section": "7", "url": "https://www.chedong.com/phpMan.php/man/man/7/json" }, { "name": "catman", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/catman/8/json" }, { "name": "mandb", "section": "8", "url": "https://www.chedong.com/phpMan.php/man/mandb/8/json" }, { "name": "info", "section": "1", "url": "https://www.chedong.com/phpMan.php/man/info/1/json" } ], "tldr": { "source": "official", "description": "Format and display manual pages.", "examples": [ { "description": "Display the man page for a command", "command": "man {{command}}" }, { "description": "Open the man page for a command in a browser (`=browser_name` can be omitted if `$BROWSER` is set)", "command": "man {{-H|--html=}}{{browser_name}} {{command}}" }, { "description": "Display the man page for a command from section 7", "command": "man 7 {{command}}" }, { "description": "List all available sections for a command", "command": "man {{-f|--whatis}} {{command}}" }, { "description": "Display the path searched for manpages", "command": "man {{-w|--path}}" }, { "description": "Display the location of a manpage rather than the manpage itself", "command": "man {{-w|--where}} {{command}}" }, { "description": "Display the man page using a specific locale", "command": "man {{-L|--locale}} {{locale}} {{command}}" }, { "description": "Search for manpages containing a search string", "command": "man {{-k|--apropos}} \"{{search_string}}\"" } ] } }