The “whatis” command in Linux is a simple utility that provides a brief description of another command available on Linux system. “whatis” command takes the name of the program or command as an argument and returns a one-line summary of what it does.
This command can be normally used to quickly find information about a specific command by new users or if we come across some command for which we don’t know the purpose of that command.
For example : To find information about the “find” command, we can run the following command:
$ whatis find
and the output of this command is,
$ whatis find find (1) - search for files in a directory hierarchy
As we can see, the “whatis find” command showed us one liner description about find command which is good for quick understanding or judgement to decide command use.