What's the difference between the -d and -m options for useradd?

When we use useradd, what is the difference between -d and -m? Because the definitions of both sound similar, which is responsible for creating a home directory.

Solution 1:

The 2 options are not really similar, but they can work together. If you look at the manpage of useradd you'll find the following:

       -d, --home-dir HOME_DIR
           The new user will be created using HOME_DIR as the value for the user's login
           directory. The default is to append the LOGIN name to BASE_DIR and use that as the
           login directory name. The directory HOME_DIR does not have to exist but will not be
           created if it is missing.

       -m, --create-home
           Create the user's home directory if it does not exist. The files and directories
           contained in the skeleton directory (which can be defined with the -k option) will be
           copied to the home directory.

           By default, if this option is not specified and CREATE_HOME is not enabled, no home
           directories are created.

The -d option is just to set where the home directory of the created user will be but it will not create it if it doesn't exist. While the -m option will create the home directory that is set by -d if it doesn't exist.