locate = find data files, programs, directories, & objects matching your search.

For example, let's say I'm searching for a file with the word "license" in the filename:

locate license

Since you usually receive quite a long list when running locate, you'll probably want to do this:

locate license | more

-or-

locate license | less

locate searches a database called slocate.db on your hard drive which is updated every night. To manually update the database, login as root & then run:

updated

Note that locate searches by name only. To search by any other attribute, use find. To search only for commands, use whereis.