How To: UNIX Add A User To A Group

Q. How do I add a user to a group under Sun Solaris UNIX operating system from a shell
prompt or command line?

A.. You can useadd command to administer a new user login on the UNIX system. Solaris UNIX
/ HP-UX UNIX uses /etc/passwd, /etc/shadow and /etc/group files to store user information.

Following information is compatible with the Solaris, AIX and HP-UX UNIX operating systems.

Add A New User To A Group

Add a new user called Animesh to a group called vsftp, enter:
# useradd -G vsftp -d /data/home/v/vivek -m Animesh
# passwd Animesh
Where,

-G vsftp : Add Animesh to secondary group called vsftp. This group must exists on the system.
-d /data/home/v/vivek : Path to the vivek's home directory
-m : Create the new user's home directory if it does not already exist.
Animesh : Username / login nane

UNIX Add Existing User To A Secondary Group

Use usermod command to modify a user's login definition on the system including group membership. For, example add
user vivek to sales group, enter:
# usermod -G sales vivek
Add user tom to sales but also keep his existing membership of ftpusers, enter:
# usermod -G ftpusers,sales tom

UNIX Add Existing User To A Primary Group

Add Animesh to sales primary group and change its existing group membership:
# usermod -g sales Animesh