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 [-?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 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.
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 -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 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 con‐
tain 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 filesys‐
tem 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 hierar‐
chy. 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 avail‐
able on your system) via use of locale functions. To activate such support, it is necessary to set either
For information regarding other features and extensions available with this manual pager, please read the doc‐
uments 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 com‐
press 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 vari‐
able $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.
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 cor‐
rect 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 interro‐
gates various environment variables, possibly including $LC_MESSAGES and $LANG. To temporarily over‐
ride 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
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 reason‐
able 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 equiva‐
lent to a single manual page name containing a hyphen or an underscore. This supports the common pat‐
tern 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
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.
If you want to override man's prompt string processing completely, use the $MANLESS environment vari‐
able 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 dis‐
played 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
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 cho‐
sen 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.
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.
MANPAGER, PAGER
If $MANPAGER or $PAGER is set ($MANPAGER is used in preference), its value is used as the name of the
program used to display the manual page. By default, less -s is used.
The value may be a simple command name or a command with arguments, and may use shell quoting (back‐
slashes, 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 stan‐
dard input.
MANLESS
If $MANLESS is set, man will not perform any of its usual processing to set up a prompt string for the
less pager. Instead, the value of $MANLESS will be copied verbatim into $LESS. For example, 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 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 an ioctl(2) if available, the value of $COLUMNS, 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 typograph‐
ical 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.
/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), man‐
path(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 ([email protected]).
Dec 23 1992: Rik Faith ([email protected]) applied bug fixes supplied by Willem Kasdorp
([email protected]).
30th April 1994 - 23rd February 2000: Wilf. ([email protected]) has been developing and maintaining
this package with the help of a few dedicated people.
30th October 1996 - 30th March 2001: Fabrizio Polacco <[email protected]> maintained and enhanced this pack‐
age for the Debian project, with the help of all the community.
31st March 2001 - present day: Colin Watson <[email protected]> is now developing and maintaining man-db.
2.6.3 2012-09-17 MAN(1)
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