userdel : delete a user account
[SYNOPSIS] userdel OPTION USER
OPTION
-f force some actions that would fail otherwise
e.g. removal of user still logged in or files, even if not owned by the user
-h display this help message and exit
-r remove home directory and mail spool
-R CHROOT_DIR directory to chroot into
-P PREFIX_DIR prefix directory where are located the /etc/* files
-Z remove any SELinux user mapping for the user