Provided by: man-db_2.10.2-1_amd64 bug


       man - an interface to the system reference manuals


       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 ...


       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),
       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,

       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.


       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 -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

       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.


       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:


       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.


       The  order of sections to search may be overridden by the environment variable $MANSECT or
       by the SECTION directive in /etc/manpath.config.  By default it is as follows:

              1 n l 8 3 0 2 3posix 3pm 3perl 3am 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.


       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.

              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 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

       -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.

              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.

              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.

              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)

              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

                $ man -aw git diff

              To disable this behaviour, use the --no-subpages option.

                $ man -aw --no-subpages git diff

   Controlling formatted output
       -P pager, --pager=pager
              Specify which output pager to use.  By default, man uses pager, falling back to cat
              if pager is not found or is not executable.  This option  overrides  the  $MANPAGER
              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

              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  (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.

              Print a short usage message and exit.

       -V, --version
              Display version information.


       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.


              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.

              Every time man invokes the formatter (nroff, troff, or groff), it adds the contents
              of $MANROFFOPT to the formatter's command line.

              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.

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

              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, falling back to cat if pager 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.

              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.

              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.

              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.

              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.

              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

              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.

              If  the  $PIPELINE_DEBUG  environment  variable  is set to "1", then man will print
              debugging messages to standard error describing each subprocess it runs.

              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.


              man-db configuration file.

              A global manual page hierarchy.


       apropos(1), groff(1), less(1),  manpath(1),  nroff(1),  troff(1),  whatis(1),  zsoelim(1),
       manpath(5), man(7), catman(8), mandb(8)

       Documentation  for  some  packages  may  be available in other formats, such as info(1) or


       1990, 1991 – Originally written by John W. Eaton (

       Dec 23 1992: Rik Faith ( applied bug fixes  supplied  by  Willem  Kasdorp

       30th  April  1994  –  23rd  February  2000:  Wilf.  (  has  been
       developing and maintaining this package with the help of a few dedicated people.

       30th October 1996 – 30th March 2001: Fabrizio Polacco <> maintained and
       enhanced this package for the Debian project, with the help of all the community.

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