Linux - User & Group Management

User management permits administrative access to the users in the system which includes creating a user account and password, updating, checking, and deleting the user accounts.

User management commands

1. Create a user account

    # Create a user [syntax: useradd <user_name>] 
    ubuntu@ip-172-31-85-161:~$ sudo useradd Joe
    # Create a user with a user folder in /home directory [syntax: useradd -m <user_name>]
    ubuntu@ip-172-31-85-161:/home$ sudo useradd -m Steve
   

2. To verify/check the user account properties

    ubuntu@ip-172-31-85-161:/home$ sudo cat /etc/passwd
   

3. Create a user account password

    # [syntax: passwd <user_name>] 
    ubuntu@ip-172-31-85-161:/home$ sudo passwd Steve 
    New password: 
    Retype new password: 
    passwd: password updated successfully
   

4. To verify/check the password properties

    ubuntu@ip-172-31-85-161:/home$ sudo cat /etc/shadow
   

5. Switch user account

    # [syntax: su <username>]
    ubuntu@ip-172-31-85-161:/home$ su Steve
   

6. Delete the user account

    # [syntax: userdel <user_name>]
    ubuntu@ip-172-31-85-161:/home$ sudo userdel Steve
   

7. Change the user login name

    # [syntax: usermod -l <new_login_name> <old_login_name>
    ubuntu@ip-172-31-85-161:/home$ sudo usermod -l Steve@11 Steve
    # To verify the login name change
    ubuntu@ip-172-31-85-161:/home$ grep Steve@11 /etc/passwd
    Steve@11:x:1003:1003::/home/Steve:/bin/sh
   

8. Logout from the user account

    # use exit or press the ctrl+d key   
    $ exit
   

Group management commands

Group management is a collection of user accounts that include administrative access to the group, managing, and giving permissions to several users.

1. Create group account

    ubuntu@ip-172-31-85-161:/home$ sudo groupadd testgrp
   

2. Add a single member to a group

    # [Syntax: gpasswd -a <user_name><group_name>]
    ubuntu@ip-172-31-85-161:~$ sudo gpasswd -a Steven testgrp 
    Adding user Steven to group testgrp
   

3. Add multiple members to a group

    # [Syntax: gpasswd -M <users_name> <group_name>]
    ubuntu@ip-172-31-85-161:~$ sudo gpasswd -M Joe,ubuntu testgrp
   

4. To verify/check the group account properties

    ubuntu@ip-172-31-85-161:/home$ sudo cat /etc/group
   

5. To verify/check the group admin properties

    ubuntu@ip-172-31-85-161:~$ sudo cat /etc/gshadow
   

6. To make a group admin

    # [syntax: gpasswd -A <user_name> <group_name>]
    ubuntu@ip-172-31-85-161:~$ sudo gpasswd -A Steven testgrp
   

7. To remove a group member

    # [syntax: gpasswd -d <user_name> <group_name>]
    ubuntu@ip-172-31-85-161:~$ sudo gpasswd -d ubuntu testgrp 
    Removing user ubuntu from group testgrp
   

8. To delete the group account

    # [syntax: groupdel <group_name>]
    ubuntu@ip-172-31-85-161:~$ sudo groupdel testgrp