All user information is normally listed in the "/etc/passwd" file and the group information in the "/etc/groups" file.
If you need to edit either file it is recommended that you use vipw to edit the password file and vigr to edit the group file. These particular commands take care of any
processing and locking of the files before and after editing them.
There is a lot of information about adding/removing/controlling users and groups, this information is only the minimal information required.
chsh Used to change your login shell.
To list the shells available type:
Simply type chsh then [Enter], then type the name of the shell you would like to use every time you login.
chfn Change finger information.
The information this command changes is reflected in the /etc/passwd file, use this utility to update your real name, office and home phone numbers (if they exist).
Use the -f option to change a user's full name. Use this tool as either chfn or chfn user_name (usable by root only).
passwd Changes the password of a user. You will need to be root if you want to change other user's passwords.
Simply type passwd to change your own password or to change another user's password type: