# Get Help With A Command

The --help argument is a common choice for quickly learning about a command. Particularly useful, --help shows the arguments for that particular command so we don’t have to look them up online.

Another option is the whatis command, which prints a one-line description of the command.

## Quickly Describe A Command

whatis mkdir
mkdir (1)            - make directories
mkdir (2)            - create a directory


Note that in this case there are two mkdir commands with slightly different descriptions, but you can ignore that.

## Get Help With A Command

In this example, we get help for the command mkdir (make directory).

mkdir --help
Usage: mkdir [OPTION]... DIRECTORY...
Create the DIRECTORY(ies), if they do not already exist.

Mandatory arguments to long options are mandatory for short options too.
-m, --mode=MODE   set file mode (as in chmod), not a=rwx - umask
-p, --parents     no error if existing, make parent directories as needed
-v, --verbose     print a message for each created directory
-Z                   set SELinux security context of each created directory
to the default type
--context[=CTX]  like -Z, or if CTX is specified then set the SELinux
or SMACK security context to CTX
--help     display this help and exit
--version  output version information and exit