MAN(1)                         Manual pager utils                         MAN(1)



NAME
       man - an interface to the on-line reference manuals

SYNOPSIS
       man [-C file] [-d] [-D] [--warnings[=warnings]] [-R encoding] [-L locale]
       [-m  system[,...]]  [-M  path]   [-S   list]   [-e   extension]   [-i|-I]
       [--regex|--wildcard]  [--names-only] [-a] [-u] [--no-subpages] [-P pager]
       [-r prompt] [-7] [-E  encoding]  [--no-hyphenation]  [--no-justification]
       [-p  string]  [-t]  [-T[device]]  [-H[browser]] [-X[dpi]] [-Z] [[section]
       page ...] ...
       man -k [apropos options] regexp ...
       man -K [-w|-W] [-S list] [-i|-I] [--regex] [section] term ...
       man -f [whatis options] page ...
       man -l [-C file] [-d]  [-D]  [--warnings[=warnings]]  [-R  encoding]  [-L
       locale]  [-P  pager]  [-r  prompt]  [-7]  [-E  encoding] [-p string] [-t]
       [-T[device]] [-H[browser]] [-X[dpi]] [-Z] file ...
       man -w|-W [-C file] [-d] [-D] page ...
       man -c [-C file] [-d] [-D] page ...
       man [-hV]

DESCRIPTION
       man is the system's manual pager. Each page argument given to man is nor‐
       mally  the name of a program, utility or function.  The manual page asso‐
       ciated with each of these arguments is then found and displayed.  A  sec‐
       tion,  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  sec‐
       tions,  following  a  pre-defined  order  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.


       tab (@); l lx.  1@T{ Executable programs or shell commands T} 2@T{ System
       calls (functions provided by the kernel) T} 3@T{ Library calls (functions
       within  program  libraries) T} 4@T{ Special files (usually found in /dev)
       T} 5@T{ File formats and conventions eg /etc/passwd T} 6@T{ Games T} 7@T{
       Miscellaneous  (including  macro  packages and conventions), e.g. man(7),
       groff(7) T} 8@T{ System administration commands (usually only  for  root)
       T} 9@T{ Kernel routines [Non standard] T}

       A manual page consists of several sections.

       Conventional   section   names  include  NAME,  SYNOPSIS,  CONFIGURATION,
       DESCRIPTION, OPTIONS,  EXIT STATUS,  RETURN VALUE,  ERRORS,  ENVIRONMENT,
       FILES,  VERSIONS,  CONFORMING TO,  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.


       tab  (@);  l  lx.  bold text@T{ type exactly as shown.  T} italic text@T{
       replace with appropriate argument.  T} [-abc]@T{  any  or  all  arguments
       within  [  ]  are optional.  T} -a|-b@T{ options delimited by | cannot be
       used together.  T} argument ...@T{ argument is repeatable.   T}  [expres‐
       sion] ...@T{ entire expression within [ ] is repeatable.  T}

       Exact  rendering  may vary depending on the output device.  For instance,
       man will usually not be able to render italics when running in  a  termi‐
       nal, 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  sev‐
       eral  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 -a intro
           Display, in succession, all of the available intro manual pages  con‐
           tained  within the manual.  It is possible to quit between successive
           displays or skip any of them.

       man -t alias | lpr -Pps
           Format the manual page referenced by `alias', usually a shell  manual
           page,  into  the  default  troff  or  groff format and pipe it to the
           printer named ps.  The default output  for  groff  is  usually  Post‐
           Script.   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 expression.  Print out any matches.  Equivalent to
           apropos -r printf.

       man -f smail
           Lookup the manual pages referenced by smail and print out  the  short
           descriptions of any found.  Equivalent to whatis -r 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 back‐
       slash).  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.

       The manual pager utilities packaged as man-db make extensive use of index
       database caches.  These caches contain information  such  as  where  each
       manual page can be found on the filesystem and what its whatis (short one
       line description of the man page) contains, and allow man to  run  faster
       than if it had to search the filesystem each time to find the appropriate
       manual page.  If requested using the -u option, man will ensure that  the
       caches  remain  consistent,  which  can  obviate the need to manually run
       software to update traditional whatis text databases.

       If man cannot find a mandb initiated index database for a particular man‐
       ual  page hierarchy, it will still search for the requested manual pages,
       although file globbing will be necessary to search within that hierarchy.
       If whatis or apropos fails to find an index it will try to extract infor‐
       mation from a traditional whatis database instead.

       These utilities support compressed source nroff files having, by default,
       the  extensions  of .Z, .z and .gz.  It is possible to deal with any com‐
       pression extension, but this information must be known at  compile  time.
       Also, by default, any cat pages produced are compressed using gzip.  Each
       `global' manual page hierarchy such as /usr/share/man  or  /usr/X11R6/man
       may  have any directory as its cat page hierarchy.  Traditionally the cat
       pages are stored under the same hierarchy as the man pages, but for  rea‐
       sons such as those specified in the File Hierarchy Standard (FHS), it may
       be better to store them elsewhere.  For details on how to do this, please
       read manpath(5).  For details on why to do this, read the standard.

       International  support  is  available with this package.  Native language
       manual pages are accessible (if available on  your  system)  via  use  of
       locale  functions.   To  activate  such  support,  it is necessary to set
       either $LC_MESSAGES, $LANG or another system dependent environment  vari‐
       able to your language locale, usually specified in the POSIX 1003.1 based
       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.

       Support  for  international  message  catalogues is also featured in this
       package and can be activated in the same way, again if available.  If you
       find  that  the  manual  pages  and message catalogues 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.

       For information regarding other features and  extensions  available  with
       this manual pager, please read the documents supplied with the package.

DEFAULTS
       man  will  search  for the desired manual pages within the index database
       caches. If the -u option is given, a cache consistency check is performed
       to  ensure  the  databases  accurately  reflect  the filesystem.  If this
       option is always given, it is not generally necessary to run mandb  after
       the  caches  are initially created, unless a cache becomes corrupt.  How‐
       ever, the cache consistency check can be slow on systems with many manual
       pages  installed,  so it is not performed by default, and system adminis‐
       trators may wish to run mandb every week  or  so  to  keep  the  database
       caches  fresh.  To forestall problems caused by outdated caches, man will
       fall back to file globbing if a cache lookup fails, just as it  would  if
       no cache was present.

       Once  a manual page has been located, a check is performed to find out if
       a relative preformatted `cat' file already exists and is newer  than  the
       nroff  file.   If  it  does  and  is, this preformatted file is (usually)
       decompressed and then displayed, via use of a pager.  The  pager  can  be
       specified  in  a  number  of ways, or else will fall back to a default is
       used (see option -P for details).  If no cat is found or  is  older  than
       the  nroff  file,  the  nroff is filtered through various programs and is
       shown immediately.

       If a cat file can be produced (a relative cat directory  exists  and  has
       appropriate permissions), man will compress and store the cat file in the
       background.

       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  format‐
       ter  (nroff or [tg]roff with -t) and executed.  Alternatively, if an exe‐
       cutable 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".  See the “Warnings” node in  info  groff  for  a
              list of available warning names.

   Main modes of operation
       -f, --whatis
              Equivalent to whatis.  Display a short description from the manual
              page, if available. See whatis(1) for details.

       -k, --apropos
              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.

       -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.  When
              this option is not used, and man fails to find the page  required,
              before displaying the error message, it attempts to act as if this
              option was supplied, using the name as a filename and looking  for
              an exact match.

       -w, --where, --location
              Don't  actually  display  the manual pages, but do print the loca‐
              tion(s) of the source nroff files that would be formatted.

       -W, --where-cat, --location-cat
              Don't actually display the manual pages, but do  print  the  loca‐
              tion(s)  of  the  cat files that would be displayed.  If -w and -W
              are both specified, print both separated by a space.

       -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 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.

   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 vari‐
              ables,  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  system's  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 oper‐
              ating 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  vari‐
              able.

       -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  over‐
              rides 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 man‐
              ual (under "The manual page system").  To view manual  pages  out‐
              side such hierarchies, see the -l option.

       -S list, -s list, --sections=list
              List  is a colon- or comma-separated list of `order specific' man‐
              ual sections to search.  This option overrides the $MANSECT  envi‐
              ronment variable.  (The -s spelling is for compatibility with Sys‐
              tem 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 oper‐
              ation,  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 wild‐
              cards, 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  man‐
              ual  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 perform  an  `inode  level'  consistency
              check  on  its database caches to ensure that they are an accurate
              representation of the filesystem.  It  will  only  have  a  useful
              effect if man is installed with the setuid bit set.

       --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 com‐
              mon 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  sub‐
              commands 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 pager -s.
              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  argu‐
              ments,  and  may use shell quoting (backslashes, single quotes, or
              double quotes).  It may not use pipes  to  connect  multiple  com‐
              mands;  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  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.

              If you want to override man's prompt string processing completely,
              use the $MANLESS environment variable described below.

       -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.


              tab  (@);  l c c c.  Description@Octal@latin1@ascii _ T{ continua‐
              tion hyphen T}@255@‐@- T{ bullet (middle dot) T}@267@·@o T{  acute
              accent T}@264@´@' T{ multiplication sign T}@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 hyphen‐
              ated 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  pre‐
              processors.   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 (provided with Groff-1.17) include dvi, latin1, ps,
              utf8, X75 and X100.

       -H[browser], --html[=browser]
              This option will cause groff to produce HTML output, and will dis‐
              play  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
       -h, --help
              Print a help 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.

       MANROFFOPT
              The contents of $MANROFFOPT are added to the  command  line  every
              time man invokes the formatter (nroff, troff, or groff).

       MANROFFSEQ
              If  $MANROFFSEQ  is set, its value is used to determine the set of
              preprocessors to pass each manual page through.  The default  pre‐
              processor list is system dependent.

       MANSECT
              If  $MANSECT  is  set, its value is a colon-delimited list of sec‐
              tions and it is used to determine which manual sections to  search
              and in what order.

       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, pager -s is used.

              The  value  may  be  a simple command name or a command with argu‐
              ments, and may use shell quoting (backslashes, single  quotes,  or
              double  quotes).   It  may  not use pipes to connect multiple com‐
              mands; 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, man will not perform any of its usual process‐
              ing to set up a prompt string for the less  pager.   Instead,  the
              value  of  $MANLESS will be copied verbatim into $LESS.  For exam‐
              ple, if you want to set the prompt string unconditionally  to  “my
              prompt string”, set $MANLESS to ‘-Psmy prompt string’.

       BROWSER
              If  $BROWSER  is  set, its value is a colon-delimited list of com‐
              mands, 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 cur‐
              rent  terminal (using an ioctl(2) if available, the value of $COL‐
              UMNS, 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  format‐
              ting  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 for‐
              matted 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.

       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  avail‐
              able).  See setlocale(3) for precise details.

FILES
       /etc/manpath.config
              man-db configuration file.

       /usr/share/man
              A global manual page hierarchy.

       /usr/share/man/index.(bt|db|dir|pag)
              A traditional global index database cache.
       /var/cache/man/index.(bt|db|dir|pag)
              An FHS compliant global index database cache.

SEE ALSO
       apropos(1), groff(1), less(1), manpath(1), nroff(1), troff(1), whatis(1),
       zsoelim(1), setlocale(3), manpath(5), ascii(7), latin1(7),  man(7),  cat‐
       man(8), mandb(8), the man-db package manual, FSSTND

HISTORY
       1990, 1991 - Originally written by John W. Eaton (jwe@che.utexas.edu).

       Dec  23  1992: Rik Faith (faith@cs.unc.edu) applied bug fixes supplied by
       Willem Kasdorp (wkasdo@nikhefk.nikef.nl).

       30th April 1994 - 23rd February 2000:  Wilf.  (G.Wilford@ee.surrey.ac.uk)
       has  been  developing and maintaining this package with the help of a few
       dedicated people.

       30th  October  1996  -  30th   March   2001:   Fabrizio   Polacco   <fpo‐
       lacco@debian.org>  maintained  and  enhanced  this package for the Debian
       project, with the help of all the community.

       31st March 2001 - present day: Colin Watson <cjwatson@debian.org> is  now
       developing and maintaining man-db.



2.6.2                              2012-06-18                             MAN(1)