Section: Manual pager utils (1)
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.
-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.
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