# man

## NAME



           man - an interface to the system reference manuals
    


## SYNOPSIS



           **man**[_man options_] [[_section_] _page_ ...] ...
           **man -k**[_apropos options_] _regexp_ ...
           **man -K**[_man options_] [_section_] _term_ ...
           **man -f**[_whatis options_] _page_ ...
           **man -l**[_man options_] _file_ ...
           **man -w** |**-W**[_man options_] _page_ ...
    


## DESCRIPTION



           **man** is the system's manual pager.  Each _page_ argument given to **man**
           is normally the name of a program, utility or function.  The
           _manual page_ associated with each of these arguments is then found
           and displayed.  A _section_ , if provided, will direct **man** to look
           only in that _section_ of the manual.  The default action is to
           search in all of the available _sections_ following a pre-defined
           order (see **DEFAULTS**), and to show only the first _page_ found, even
           if _page_ exists in several _sections_.
    
           The table below shows the _section_ numbers of the manual followed
           by the types of pages they contain.
    
           1   Executable programs or shell commands
           2   System calls (functions provided by the kernel)
           3   Library calls (functions within program libraries)
           4   Special files (usually found in _/dev_)
           5   File formats and conventions, e.g. _/etc/passwd_
           6   Games
           7   Miscellaneous (including macro packages and conventions), e.g.
               man(7), groff(7), man-pages(7)
           8   System administration commands (usually only for root)
           9   Kernel routines [Non standard]
    
           A manual _page_ consists of several sections.
    
           Conventional section names include **NAME** , **SYNOPSIS** , **CONFIGURATION** ,
           **DESCRIPTION** , **OPTIONS** , **EXIT STATUS** , **RETURN VALUE** , **ERRORS** ,
           **ENVIRONMENT** , **FILES** , **VERSIONS** , **STANDARDS** , **NOTES** , **BUGS** , **EXAMPLE** ,
           **AUTHORS** , and **SEE ALSO**.
    
           The following conventions apply to the **SYNOPSIS** section and can be
           used as a guide in other sections.
    
           **bold text** type exactly as shown.
           _italic text_        replace with appropriate argument.
           [**-abc**]             any or all arguments within [ ] are optional.
           **-a** |**-b** options delimited by | cannot be used together.
           _argument_ ...       _argument_ is repeatable.
           [_expression_] ...   entire _expression_ within [ ] is repeatable.
    
           Exact rendering may vary depending on the output device.  For
           instance, man will usually not be able to render italics when
           running in a terminal, and will typically use underlined or
           coloured text instead.
    
           The command or function illustration is a pattern that should
           match all possible invocations.  In some cases it is advisable to
           illustrate several exclusive invocations as is shown in the
           **SYNOPSIS** section of this manual page.
    


## 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 alternative 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 manual.  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 -T** _dvi ./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 expression.  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_**.**
    


## OVERVIEW



           Many options are available to **man** in order to give as much
           flexibility as possible to the user.  Changes can be made to the
           search path, section order, output processor, and other behaviours
           and operations detailed below.
    
           If set, various environment variables are interrogated to
           determine the operation of **man**.  It is possible to set the "catch-
           all" variable $**MANOPT** to any string in command line format, with
           the exception that any spaces used as part of an option's argument
           must be escaped (preceded by a backslash).  **man** will parse $**MANOPT**
           prior to parsing its own command line.  Those options requiring an
           argument will be overridden by the same options found on the
           command line.  To reset all of the options set in $**MANOPT** , **-D** can
           be specified as the initial command line option.  This will allow
           man to "forget" about the options specified in $**MANOPT** , although
           they must still have been valid.
    
           Manual pages are normally stored in nroff(1) format under a
           directory such as _/usr/share/man_.  In some installations, there
           may also be preformatted _cat pages_ to improve performance.  See
           manpath(5) for details of where these files are stored.
    
           This package supports manual pages in multiple languages,
           controlled by your _locale_.  If your system did not set this up for
           you automatically, then you may need to set $**LC_MESSAGES** , $**LANG** ,
           or another system-dependent environment variable to indicate your
           preferred locale, usually specified in the **POSIX** format:
    
           <_language_ >[**_** <_territory_ >[**.** <_character-set_ >[**,** <_version_ >]]]
    
           If the desired page is available in your _locale_ , it will be
           displayed in lieu of the standard (usually American English) page.
    
           If you find that the translations supplied with this package are
           not available in your native language and you would like to supply
           them, please contact the maintainer who will be coordinating such
           activity.
    
           Individual manual pages are normally written and maintained by the
           maintainers of the program, function, or other topic that they
           document, and are not included with this package.  If you find
           that a manual page is missing or inadequate, please report that to
           the maintainers of the package in question.
    
           For information regarding other features and extensions available
           with this manual pager, please read the documents supplied with
           the package.
    


## DEFAULTS



           The order of sections to search may be overridden by the
           environment variable $**MANSECT** or by the **SECTION** directive in
           _/usr/local/etc/man_db.conf_.  By default it is as follows:
    
                  1 n l 8 3 0 2 3type 5 4 9 6 7
    
           The formatted manual page is displayed using a _pager_.  This can be
           specified in a number of ways, or else will fall back to a default
           (see option **-P** for details).
    
           The filters are deciphered by a number of means.  Firstly, the
           command line option **-p** or the environment variable $**MANROFFSEQ** is
           interrogated.  If **-p** was not used and the environment variable was
           not set, the initial line of the nroff file is parsed for a
           preprocessor string.  To contain a valid preprocessor string, the
           first line must resemble
    
           **'\"** <**string** >
    
           where **string** can be any combination of letters described by option
           **-p** below.
    
           If none of the above methods provide any filter information, a
           default set is used.
    
           A formatting pipeline is formed from the filters and the primary
           formatter (**nroff** or [**tg**]**roff** with **-t**) and executed.
           Alternatively, if an executable program _mandb_nfmt_ (or _mandb_tfmt_
           with **-t**) exists in the man tree root, it is executed instead.  It
           gets passed the manual source file, the preprocessor string, and
           optionally the device specified with **-T** or **-E** as arguments.
    


## OPTIONS



           Non-argument options that are duplicated either on the command
           line, in $**MANOPT** , or both, are not harmful.  For options that
           require an argument, each duplication will override the previous
           argument value.
    
       **General options**
           **-C** _file_ , **--config-file=**_file_
                  Use this user configuration file rather than the default of
                  _~/.manpath_.
    
           **-d** , **--debug**
                  Print debugging information.
    
           **-D** , **--default**
                  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.
    
       **Main modes of operation**
           **-f** , **--whatis**
                  Approximately equivalent to **whatis**.  Display a short
                  description from the manual page, if available.  See
                  whatis(1) for details.
    
           **-k** , **--apropos**
                  Approximately equivalent to **apropos**.  Search the short
                  manual page descriptions for keywords and display any
                  matches.  See apropos(1) for details.
    
           **-K** , **--global-apropos**
                  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 regular 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
                  negatives due to things like hyphens being written as "\-"
                  in source files.  Searching the rendered text would be much
                  slower.
    
           **-l** , **--local-file**
                  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.
    
           **-w** , **--where** , **--path** , **--location**
                  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.
    
           **-W** , **--where-cat** , **--location-cat**
                  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
                  locations 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.
    
           **-c** , **--catman**
                  This option is not for general use and should only be used
                  by the **catman** program.
    
           **-R** _encoding_ , **--recode** =_encoding_
                  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 manual 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.
    
       **Finding manual pages**
           **-L** _locale_ , **--locale=**_locale_
                  **man** will normally determine your current locale by a call
                  to the C function setlocale(3) which interrogates various
                  environment variables, possibly including $**LC_MESSAGES** 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 displayed in the initially determined
                  locale.
    
           **-m** _system_[,...], **--systems=**_system_[,...]
                  If this system has access to other operating systems'
                  manual pages, they can be accessed using this option.  To
                  search for a manual page from NewOS's manual page
                  collection, 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.
    
           **-M** _path_ , **--manpath=**_path_
                  Specify an alternate manpath to use.  By default, **man** uses
                  **manpath** derived code to determine 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.
    
           **-S** _list_ , **-s** _list_ , **--sections=**_list_
                  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.)
    
           **-e** _sub-extension_ , **--extension=**_sub-extension_
                  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 indicating 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**.
    
           **-i** , **--ignore-case**
                  Ignore case when searching for manual pages.  This is the
                  default.
    
           **-I** , **--match-case**
                  Search for manual pages case-sensitively.
    
           **--regex**
                  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 option implies **-a**.
    
           **--wildcard**
                  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**.
    
           **--names-only**
                  If the **--regex** or **--wildcard** option is used, match only
                  page names, not page descriptions, as with whatis(1).
                  Otherwise, no effect.
    
           **-a** , **--all**
                  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.
    
           **-u** , **--update**
                  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.
    
           **--no-subpages**
                  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 syntax 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
    
       **Controlling formatted output**
           **-P** _pager_ , **--pager=**_pager_
                  Specify which output pager to use.  By default, **man** uses
                  **less** , falling back to **cat** if **less** is not found or is not
                  executable.  This option overrides the $**MANPAGER**
                  environment 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 connect
                  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.
    
           **-r** _prompt_ , **--prompt=**_prompt_
                  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 variable.
    
                  Supplying **-r** with a string will override this default.  The
                  string may contain the text **$MAN_PN** 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\ \$MAN_PN\ ?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 preceding 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.
    
           **-7** , **--ascii**
                  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_ characters and this option is not
                  necessary.  If the _latin1_ and _ascii_ columns are identical,
                  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**.
    
           **-E** _encoding_ , **--encoding** =_encoding_
                  Generate output for a character encoding other than the
                  default.  For backward compatibility, _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** documentation
                  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 being
                  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 certain 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.
    
           **-p** _string_ , **--preprocessor=**_string_
                  Specify the sequence of preprocessors to run before **nroff**
                  or **troff** /**groff**.  Not all installations 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.
    
           **-t** , **--troff**
                  Use _groff -mandoc_ to format the manual page to stdout.
                  This option is not required in conjunction with **-H** , **-T** , or
                  **-Z**.
    
           **-T**[_device_], **--troff-device**[=_device_]
                  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 (as of groff 1.23.0) include **dvi** ,
                  **latin1** , **pdf** , **ps** , **utf8** , **X75** and **X100**.
    
           **-H**[_browser_], **--html**[=_browser_]
                  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**.
    
           **-X**[_dpi_], **--gxditview**[=_dpi_]
                  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.
    
           **-Z** , **--ditroff**
                  **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**.
    
       **Getting help**
           **-?** , **--help**
                  Print a help message and exit.
    
           **--usage**
                  Print a short usage message and exit.
    
           **-V** , **--version**
                  Display version information.
    


## EXIT STATUS



           **0** Successful program execution.
    
           **1** Usage, syntax or configuration file error.
    
           **2** Operational error.
    
           **3** A child process returned a non-zero exit status.
    
           **16** At least one of the pages/files/keywords didn't exist or
                  wasn't matched.
    


## ENVIRONMENT



           **MANPATH**
                  If $**MANPATH** is set, its value is used as the path to search
                  for manual pages.
    
                  See the **SEARCH PATH** section of manpath(5) for the default
                  behaviour and details of how this environment variable is
                  handled.
    
           **MANROFFOPT**
                  Every time **man** invokes the formatter (**nroff** , **troff** , or
                  **groff**), it adds the contents of $**MANROFFOPT** to the
                  formatter's command line.
    
                  For example, **MANROFFOPT=-P-i** tells the formatter to use
                  italic text (which is only supported by some terminals)
                  rather than underlined text.
    
           **MANROFFSEQ**
                  If $**MANROFFSEQ** is set, its value is used to determine the
                  set of preprocessors to pass each manual page through.  The
                  default preprocessor list is system dependent.
    
           **MANSECT**
                  If $**MANSECT** is set, its value is a colon-delimited list of
                  sections and it is used to determine which manual sections
                  to search and in what order.  The default is "1 n l 8 3 0 2
                  3type 5 4 9 6 7", unless overridden by the **SECTION**
                  directive in _/usr/local/etc/man_db.conf_.
    
           **MANPAGER** , **PAGER**
                  If $**MANPAGER** or $**PAGER** is set ($**MANPAGER** is used in
                  preference), its value is used as the name of the program
                  used to display the manual page.  By default, **less** is used,
                  falling back to **cat** if **less** is not found or is not
                  executable.
    
                  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 connect
                  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.
    
           **MANLESS**
                  If $**MANLESS** is set, its value will be used as the default
                  prompt string for the **less** pager, as if it had been passed
                  using the **-r** option (so any occurrences of the text **$MAN_PN**
                  will be expanded in the same way).  For example, if you
                  want to set the prompt string unconditionally to “my prompt
                  string”, set $**MANLESS** to ‘**-Psmy prompt string** ’.  Using the
                  **-r** option overrides this environment variable.
    
           **BROWSER**
                  If $**BROWSER** is set, its value is a colon-delimited list of
                  commands, each of which in turn is used to try to start a
                  web browser for **man --html**.  In each command, _%s_ is
                  replaced by a filename containing the HTML output from
                  **groff** , _%%_ is replaced by a single percent sign (%), and _%c_
                  is replaced by a colon (:).
    
           **SYSTEM** If $**SYSTEM** is set, it will have the same effect as if it
                  had been specified as the argument to the **-m** option.
    
           **MANOPT** If $**MANOPT** is set, it will be parsed prior to **man's** command
                  line and is expected to be in a similar format.  As all of
                  the other **man** specific environment variables can be
                  expressed as command line options, and are thus candidates
                  for being included in $**MANOPT** it is expected that they will
                  become obsolete.  N.B.  All spaces that should be
                  interpreted as part of an option's argument must be
                  escaped.
    
           **MANWIDTH**
                  If $**MANWIDTH** is set, its value is used as the line length
                  for which manual pages should be formatted.  If it is not
                  set, manual pages will be formatted with a line length
                  appropriate to the current terminal (using the value of
                  $**COLUMNS** , and ioctl(2) if available, or falling back to 80
                  characters if neither is available).  Cat pages will only
                  be saved when the default formatting can be used, that is
                  when the terminal line length is between 66 and 80
                  characters.
    
           **MAN_KEEP_FORMATTING**
                  Normally, when output is not being directed to a terminal
                  (such as to a file or a pipe), formatting characters are
                  discarded to make it easier to read the result without
                  special tools.  However, if $**MAN_KEEP_FORMATTING** is set to
                  any non-empty value, these formatting characters are
                  retained.  This may be useful for wrappers around **man** that
                  can interpret formatting characters.
    
           **MAN_KEEP_STDERR**
                  Normally, when output is being directed to a terminal
                  (usually to a pager), any error output from the command
                  used to produce formatted versions of manual pages is
                  discarded to avoid interfering with the pager's display.
                  Programs such as **groff** often produce relatively minor error
                  messages about typographical problems such as poor
                  alignment, which are unsightly and generally confusing when
                  displayed along with the manual page.  However, some users
                  want to see them anyway, so, if $**MAN_KEEP_STDERR** is set to
                  any non-empty value, error output will be displayed as
                  usual.
    
           **MAN_DISABLE_SECCOMP**
                  On Linux, **man** normally confines subprocesses that handle
                  untrusted data using a seccomp(2) sandbox.  This makes it
                  safer to run complex parsing code over arbitrary manual
                  pages.  If this goes wrong for some reason unrelated to the
                  content of the page being displayed, you can set
                  $**MAN_DISABLE_SECCOMP** to any non-empty value to disable the
                  sandbox.
    
           **PIPELINE_DEBUG**
                  If the $**PIPELINE_DEBUG** environment variable is set to "1",
                  then **man** will print debugging messages to standard error
                  describing each subprocess it runs.
    
           **LANG** , **LC_MESSAGES**
                  Depending on system and implementation, either or both of
                  $**LANG** and $**LC_MESSAGES** will be interrogated for the current
                  message locale.  **man** will display its messages in that
                  locale (if available).  See setlocale(3) for precise
                  details.
    


## FILES



           _/usr/local/etc/man_db.conf_
                  man-db configuration file.
    
           _/usr/share/man_
                  A global manual page hierarchy.
    


## STANDARDS



           POSIX.1-2001, POSIX.1-2008, POSIX.1-2017.
    


## BUGS



           https://gitlab.com/man-db/man-db/-/issues
           https://savannah.nongnu.org/bugs/?group=man-db
    


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