Ubuntu useradd command

Ubuntu useradd command is a traditional Linux command to create a new user in the system. It is a low level utility for adding user or change new user default information. If you are new in Ubuntu, use the upper level utility, the adduser command instead.

Here are basic useradd command information:

• Name: useradd - create a new user or update default new user information.
• Synopsis:

useradd [options] LOGIN

useradd -D

useradd -D [options]

When invoked without the -D option, the useradd command creates a new user account using the values specified on the command line plus the default values from the system.

Ubuntu useradd command complete options:

 -b, --base-dir BASE_DIR       base directory for the new user account
                               home directory
 -c, --comment COMMENT         set the GECOS field for the new user account
 -d, --home-dir HOME_DIR       home directory for the new user account
 -D, --defaults                print or save modified default useradd
                               configuration
 -e, --expiredate EXPIRE_DATE  set account expiration date to EXPIRE_DATE
 -f, --inactive INACTIVE       set password inactive after expiration
                               to INACTIVE
 -g, --gid GROUP               force use GROUP for the new user account
 -G, --groups GROUPS           list of supplementary groups for the new
                               user account
 -h, --help                    display this help message and exit
 -k, --skel SKEL_DIR           specify an alternative skel directory
 -K, --key KEY=VALUE           overrides /etc/login.defs defaults
 -m, --create-home             create home directory for the new user
                               account
 -o, --non-unique              allow create user with duplicate
                               (non-unique) UID
 -p, --password PASSWORD       use encrypted password for the new user
                               account
 -r, --system                  create a system account
 -s, --shell SHELL             the login shell for the new user account
 -u, --uid UID                 force use the UID for the new user account

Here are some examples on how to use useradd options when creating a new user account:

Example 1 - Ubuntu useradd command for creating a normal user account.

luzar@ubuntu:~$ sudo useradd -c 'Normal user' -d /home/jimi -m jimi
luzar@ubuntu:~$ sudo passwd jimi
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
luzar@ubuntu:~$ ls -l /home/
total 12
drwxr-xr-x 2 aura aura 4096 2008-10-23 22:36 aura
drwxr-xr-x 2 jimi jimi 4096 2008-10-23 23:48 jimi
drwxr-xr-x 7 luzar luzar 4096 2008-10-23 05:43 luzar
luzar@ubuntu:~$

I used -c option to add comment to the user account. The -d is a home directory name and -m is to create home directory for the new user account. Finally, create a password for the new account to enabled it.

Example 2 - Ubuntu useradd command for creating user account for a temporary stuff.

luzar@ubuntu:~$ sudo useradd -c 'Temporary stuff' -e 2009-01-01 -f 7 -d /home/alex -m alex
luzar@ubuntu:~$ sudo passwd alex
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully

In the example above, I add -e option to change default values for expired date and -f for the number of days the account will be disabled after the password has expired. Then, as usual, don't forget to create a password for the new account.