man man Command

Man page for apt-get man Command

Man Page for man in Linux

Ubuntu Man Command : man man

Man Man  Command

This tutorial shows the man page for man man in linux.

Open terminal with 'su' access and type the command as shown below:
man man

Result of the Command Execution shown below:

MAN(1)                                                                   Manual pager utils                                                                   MAN(1)



NAME
man an interface to the on line reference manuals

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

DESCRIPTION
man is the system's manual pager. Each page argument given to man is 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 conven Äê
tions), 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, CON Äê
FORMING 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 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 Post Äê
Script 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 apro Äê
pos 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, out Äê
put 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 speci Äê
fied 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 tra Äê
ditional 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 per Äê
formed 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 out Äê
dated 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 dupli Äê
cation 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  ÄúWarnings Äù node in info groff for a list of available warning names.

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

k, apropos
Equivalent to apropos. Search the short manual page descriptions for keywords and display any matches. See apropos(1) for details.

K, global apropos
Search for text in all manual pages. This is a brute force search, and is likely to take some time; if you can, you should specify a section to
reduce the number of pages that need to be searched. Search terms may be simple strings (the default), or regular expressions if the regex option
is used.

l, local file
Activate `local' mode. Format and display local manual files instead of searching through the system's manual collection. Each manual page argument
will be interpreted as an nroff source file in the correct format. No cat file is produced. If ' ' is listed as one of the arguments, input will be
taken from stdin. When this option is not used, and man fails to find the page required, before displaying the error message, it attempts to act as
if this option was supplied, using the name as a filename and looking for an exact match.

w, where, location
Don't actually display the manual pages, but do print the 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 deter Äê
mined 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 man Äê
ual 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. 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 s. This option overrides the $MANPAGER environment variable, which in turn overrides
the $PAGER environment variable. It is not used in conjunction with f or k.

The value may be a simple command name or a command with 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 man Äê
ual 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\%..

It is broken into two 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 variable described below.

7, ascii
When viewing a pure ascii(7) manual page on a 7 bit terminal or terminal emulator, some characters may not display correctly when using the latin1(7)
device description with GNU nroff. This option allows pure ascii manual pages to be displayed in ascii with the latin1 device. It will not translate
any latin1 text. The following table shows the translations performed: some parts of it may only be displayed properly when using GNU nroff's
latin1(7) device.


Description Octal latin1 ascii
 îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ îÄ
continuation hyphen 255  Äê
bullet (middle dot) 267 ¬" o
acute accent 264 ´ '
multiplication sign 327 "ó 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 con Äê
sult 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 $MAN Äê
ROFFSEQ 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 (pro Äê
vided 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
h, help
Print a help message and exit.

V, version
Display version information.

EXIT STATUS
0 Successful program execution.

1 Usage, syntax or configuration file error.

2 Operational error.

3 A child process returned a non zero exit status.

16 At least one of the pages/files/keywords didn't exist or wasn't matched.

ENVIRONMENT
MANPATH
If $MANPATH is set, its value is used as the path to search for manual pages.

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

MANROFFSEQ
If $MANROFFSEQ is set, its value is used to determine the set of preprocessors to pass each manual page through. The default 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.

MANPAGER, PAGER
If $MANPAGER or $PAGER is set ($MANPAGER is used in preference), its value is used as the name of the program used to display the manual page. By
default, pager s is used.

The value may be a simple command name or a command with 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, 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  Äúmy prompt string Äù, set $MANLESS to
 Äò Psmy prompt string Äô.

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 environ Äê
ment 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 format Äê
ted 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 oft


Related Topics

Apt Get Commands