If you struggle to remember Linux commands with examples and syntax, install apropos tool that searches the manual page names and descriptions. One can access basic Linux commands list using apropos. It acts as a terminal based Linux commands tutorial.
The apropos command displays a list of all topics in the man pages (i.e., the standard manual that is built into Unix-like operating systems ) that are related to the subject of a query. apropos takes its name from the English word with the same spelling (and the same pronunciation) that means relevant. It is particularly useful when searching for commands without knowing their exact names.
For example, if you don’t remember which command to use for locate. You could type “apropos locate” and the tool would return all the commands related to locate command. Please note that when you run the command it lists every single command that contains the word “locate” in its man page.
apropos’s syntax is:
apropos’s format is:
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.
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