In computing, apropos is a command to search the man page files in Unix and Unix-like operating systems. apropos takes its name from the English word with the same spelling that means relevant. It is particularly useful when searching for commands without knowing their exact names.
Often a wrapper for the
man -k command, the apropos command is used to search the ”name” sections of all manual pages for the string/s (called keyword/s) specified. The output is a list of all manual pages containing the search term in their name or description. This is often useful if one knows the action that is desired, but does not remember the exact command or page name. apropos search is case insensitive.
A related command is whatis, which is useful for obtaining a brief description about a specific command whose exact name is already known.
The following example demonstrates the output of the apropos command:
$ apropos mount free (1) - Display amount of free and used memory in the system mklost+found (8) - create a lost+found directory on a mounted Linux second extended file system mount (8) - mount a file system mountpoint (1) - see if a directory is a mountpoint ntfsmount (8) - Read/Write userspace NTFS driver. sleep (1) - delay for a specified amount of time switch_root (8) - switch to another filesystem as the root of the mount tree. umount (8) - unmount file systems
In this example, apropos is used to search for the keyword "mount", and apropos returns the indicated man pages that include the term "mount".
The following example demonstrates the output of the apropos command with an regexp keyword (abc.n) and a regular keyword:
$ apropos abc.n xzless XTestGrabControl (3) - XTest extension functions xzless (1) - view xz or lzma compressed (text) files
In this example, apropos is used to search for the keywords (with an regexp .) "abc.n" and xzless, and apropos returns the indicated man pages that include the keywords.