Managing Users

Commands for managing users:

• adduser - Command used to add user accounts.
• chage  - Used to change the time the user's password will expire.
• chfn - Change a user's finger information
• chsh - Change a user's shell.
• chgrp  - Changes the group ownership of files.
• chown  - Change the owner of file(s ) to another user.
• gpasswd  - Used to administer the /etc/group file.
• groupadd  - Create a new group.
• grpconv - Creates /etc/gshadow from the file /etc/group which converts to shadow passwords.
• grpunconv - Uses the files /etc/passwd and /etc/shadow to create /etc/passwd, then deletes /etc/shadow which converts from shadow passwords.
• groupdel - Delete a group
• groupmod  - Modify a group
• groups  - print the groups a user is in
• grpck  - Verify the integrity of group files.
• id - Print group or user ID numbers for the specified user.
• newgrp - Allows a user to log in to a new group.
• newusers  - Update and create new users in batch form.
• nologin  - Prevent non-root users from logging onto the system.
• passwd  - Used to update a user's password. The command "passwd username" will set the password for the given user.
• pwconv  - Used to create the file /etc/shadow from the file /etc/passwd to convert to shadow passwords.
• pwunconv - Uses the files /etc/passwd and /etc/shadow to create /etc/passwd, then deletes /etc/shadow to convert from shadow passwords.
• su  - run a shell with substitute user and group IDs
• useradd  - Create a new user or update default new user information
• userdel  - Delete a user account and their files from the system. The command "userdel -r newuser" will remove the user and deletes their home directory.
• usermod - Modify a user account. 

Other useful commands/examples:

find / -user username -ls		Gives a list of all files owned by username.
chown -R myuser /home/myuser		Changes ownership of all files in mysuer home directory to myuser.
chmod +s filename		Sets the uid