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apropos - Online in the Cloud

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This is the command apropos that can be run in the OnWorks free hosting provider using one of our multiple free online workstations such as Ubuntu Online, Fedora Online, Windows online emulator or MAC OS online emulator



apropos - search the manual page names and descriptions


apropos [-dalv?V] [-e|-w|-r] [-s list] [-m system[,...]] [-M path] [-L locale] [-C file]
keyword ...


Each manual page has a short description available within it. apropos searches the
descriptions for instances of keyword.

keyword is usually a regular expression, as if (-r) was used, or may contain wildcards
(-w), or match the exact keyword (-e). Using these options, it may be necessary to quote
the keyword or escape (\) the special characters to stop the shell from interpreting them.

The standard matching rules allow matches to be made against the page name and word
boundaries in the description.

The database searched by apropos is updated by the mandb program. Depending on your
installation, this may be run by a periodic cron job, or may need to be run manually after
new manual pages have been installed.


-d, --debug
Print debugging information.

-v, --verbose
Print verbose warning messages.

-r, --regex
Interpret each keyword as a regular expression. This is the default behaviour.
Each keyword will be matched against the page names and the descriptions
independently. It can match any part of either. The match is not limited to word

-w, --wildcard
Interpret each keyword as a pattern containing shell style wildcards. Each keyword
will be matched against the page names and the descriptions independently. If
--exact is also used, a match will only be found if an expanded keyword matches an
entire description or page name. Otherwise the keyword is also allowed to match on
word boundaries in the description.

-e, --exact
Each keyword will be exactly matched against the page names and the descriptions.

-a, --and
Only display items that match all the supplied keywords. The default is to display
items that match any keyword.

-l, --long
Do not trim output to the terminal width. Normally, output will be truncated to
the terminal width to avoid ugly results from poorly-written NAME sections.

-s list, --sections list, --section list
Search only the given manual sections. list is a colon- or comma-separated list of
sections. If an entry in list is a simple section, for example "3", then the
displayed list of descriptions will include pages in sections "3", "3perl", "3x",
and so on; while if an entry in list has an extension, for example "3perl", then
the list will only include pages in that exact part of the manual section.

-m system[,...], --systems=system[,...]
If this system has access to other operating system's manual page descriptions,
they can be searched using this option. To search NewOS's manual page
descriptions, 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 whatis descriptions,
include the system name man in the argument string. This option will override the
$SYSTEM environment variable.

-M path, --manpath=path
Specify an alternate set of colon-delimited manual page hierarchies to search. By
default, apropos uses the $MANPATH environment variable, unless it is empty or
unset, in which case it will determine an appropriate manpath based on your $PATH
environment variable. This option overrides the contents of $MANPATH.

-L locale, --locale=locale
apropos 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 apropos. 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.

-C file, --config-file=file
Use this user configuration file rather than the default of ~/.manpath.

-?, --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.

16 Nothing was found that matched the criteria specified.


SYSTEM If $SYSTEM is set, it will have the same effect as if it had been specified as the
argument to the -m option.

If $MANPATH is set, its value is interpreted as the colon-delimited manual page
hierarchy search path to use.

If $MANWIDTH is set, its value is used as the terminal width (see the --long
option). If it is not set, the terminal width will be calculated using the value
of $COLUMNS, an ioctl(2) if available, or falling back to 80 characters if all else

If $POSIXLY_CORRECT is set, even to a null value, the default apropos search will
be as an extended regex (-r). Nowadays, this is the default behaviour anyway.

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