Manual Pages
Please note that there are far more manual pages available from the shell prompt. Those present here are mainly pages that are needed in order to connect with a remote desktop or terminal section in order to access a shell and the rest of the manual pages.
man - an
interface to the on-line reference manuals 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 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. 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. 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. 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. 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. 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. 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 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 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 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 To disable this
behaviour, use the --no-subpages option. $ man -aw
--no-subpages git diff Controlling
formatted output 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.: 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. 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 Print a help message and
exit. --usage 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. 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. /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. 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 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.MAN
NAME
SYNOPSIS
DESCRIPTION
EXAMPLES
OVERVIEW
DEFAULTS
OPTIONS
EXIT STATUS
ENVIRONMENT
FILES
SEE ALSO
HISTORYNAME
SYNOPSIS
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
EXAMPLES
OVERVIEW
DEFAULTS
OPTIONS
-C file, --config-file=file
-f, --whatis
-L locale, --locale=locale
/usr/share/man/man1/git-diff.1.gz
/usr/share/man/man1/git.1.gz
/usr/share/man/man3/Git.3pm.gz
/usr/share/man/man1/diff.1.gz
-P pager, --pager=pager
byte\ %bB?s/%s..?\ (END):?pB\ %pB\\%..
(press h for help or q to quit)
-?, --helpEXIT STATUS
ENVIRONMENT
FILES
SEE ALSO
HISTORY