Apropos

Searches through headers of manpages for a string. It is equivalent to man -k.

Apropos is useful when you have some idea of what you want to do, but don't know the name of the tool required. For example: "apropos rename" gives lots of results, including this useful one:

mv (1)              - move (rename) files

Apropos is quite closely related to whatis and uses the same database, which is created by the makewhatis command. Neither command will function in a completely new system until makewhatis has been run for the first time.

Because apropos does a simple string search on the headers, it is liable to retrieve quite a large list of man pages, which you might want to pipe through a pager such as more or less.