Ubuntu Usermod Options

For Ubuntu 14.04.1 LTS

Usage: usermod [options] LOGIN

-c, –comment COMMENT new value of the GECOS field
-d, –home HOME_DIR new home directory for the user account
-e, –expiredate EXPIRE_DATE set account expiration date to EXPIRE_DATE
-f, –inactive INACTIVE set password inactive after expiration
-g, –gid GROUP force use GROUP as new primary group
-G, –groups GROUPS new list of supplementary GROUPS
-a, –append append the user to the supplemental GROUPS
mentioned by the -G option without removing
him/her from other groups
-h, –help display this help message and exit
-l, –login NEW_LOGIN new value of the login name
-L, –lock lock the user account
-m, –move-home move contents of the home directory to the
new location (use only with -d)
-o, –non-unique allow using duplicate (non-unique) UID
-p, –password PASSWORD use encrypted password for the new password
-R, –root CHROOT_DIR directory to chroot into
-s, –shell SHELL new login shell for the user account
-u, –uid UID new UID for the user account
-U, –unlock unlock the user account
-v, –add-subuids FIRST-LAST add range of subordinate uids
-V, –del-subuids FIRST-LAST remvoe range of subordinate uids
-w, –add-subgids FIRST-LAST add range of subordinate gids
-W, –del-subgids FIRST-LAST remvoe range of subordinate gids
-Z, –selinux-user SEUSER new SELinux user mapping for the user account

Example Use Scenario

You’re running Ubuntu with Nginx and you need to be able to access Nginx owned files without using sudo. You’re username is dev1. Add your user “dev1” to group www-data.
sudo usermod -G www-data dev1

-G chages the users secondary group, if you use the lowercase -g, it changes the users primary group.