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[.section] ...] ...
   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 [-?V]

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 ("1 n l 8 3 2 3posix 3pm 3perl
   3am 5 4 9 6 7" by default, unless overridden by the  SECTION  directive
   in /etc/manpath.config), 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 eg /etc/passwd
   6   Games
   7   Miscellaneous  (including  macro  packages  and  conventions), e.g.
       man(7), groff(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, 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.

   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.

   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 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
       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 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.

   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
   manual 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 information 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  compression  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  reasons  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
   variable 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.  However, the cache consistency check can be slow  on  systems
   with  many  manual  pages installed, so it is not performed by default,
   and system administrators 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
   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".  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.

          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.   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.
          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, --path, --location
          Don't  actually  display  the  manual  pages,  but  do print the
          location(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
          location(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  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.

   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 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
          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
          List is a colon- or comma-separated  list  of  `order  specific'
          manual  sections  to search.  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 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
          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  pager.
          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      255              -
          hyphen
          bullet (middle    267      *        o
          dot)
          acute accent      264              '
          multiplication    327              x
          sign

          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 (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
          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.

   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
          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  2  3posix
          3pm  3perl  3am  5  4  9  6 7", unless overridden by the SECTION
          directive in /etc/manpath.config.

   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 is used.

          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, an 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.

   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

   /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), catman(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
   <fpolacco@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.


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