Locating a command by keyword
You can display the man page sections that contain any of the given Keywords in their title by using the apropos command.
The apropos command considers each word separately is not case-sensitive. Words that are part of other words are also displayed. For example, when looking for the word compile, the apropos command also finds all instances of the word compiler.
Note: The database containing the keywords is /usr/share/man/whatis, which must first be generated with the catman -w command.
The apropos command is equivalent to using the man command with the -k option.
For example, to find the manual sections that contain the word password in their titles, run the following command:
apropos password