How to use the command gpasswd (with examples)

The gpasswd command is used to administer /etc/group and /etc/gshadow on Linux systems. It allows you to define group administrators, set the list of group members, create a password for a named group, add users to a named group, and remove users from a named group.

Use case 1: Define group administrators

Code:

sudo gpasswd -A user1,user2 group

Motivation: This use case is useful when you want to designate certain users as administrators for a specific group. Group administrators have the ability to add or remove group members, as well as change the group’s password.

Explanation:

• sudo: Executes the command with root privileges.
• gpasswd: The command name.
• -A: Specifies that we want to define group administrators.
• user1,user2: A comma-separated list of usernames to be added as group administrators.
• group: The name of the group we want to modify.

Example output:

Adding user1 to the list of group administrators in group 'group'...
Adding user2 to the list of group administrators in group 'group'...

Use case 2: Set the list of group members

Code:

sudo gpasswd -M user1,user2 group

Motivation: This use case is helpful when you need to specify the exact list of users who should be members of a particular group. It allows you to easily manage the group membership.

Explanation:

• sudo: Executes the command with root privileges.
• gpasswd: The command name.
• -M: Specifies that we want to set the list of group members.
• user1,user2: A comma-separated list of usernames to be added as group members.
• group: The name of the group we want to modify.

Example output:

Setting the list of group members for group 'group'...
Adding user1 to the group 'group'...
Adding user2 to the group 'group'...

Use case 3: Create a password for the named group

Code:

gpasswd group

Motivation: This use case is useful when you want to assign a password to a specific group, which allows authorized users to join the group by providing the correct password.

Explanation:

• gpasswd: The command name.
• group: The name of the group for which you want to create a password.

Example output:

Enter new password:
Confirm new password:
Password successfully set for group 'group'.

Use case 4: Add a user to the named group

Code:

gpasswd -a user group

Motivation: This use case is handy when you need to add a user to a particular group. By doing this, you grant them access to any resources or permissions associated with the group.

Explanation:

• gpasswd: The command name.
• -a: Specifies that we want to add a user to a group.
• user: The username of the user to be added.
• group: The name of the group to which the user should be added.

Example output:

Adding user to the group 'group'...

Use case 5: Remove a user from the named group

Code:

gpasswd -d user group

Motivation: This use case is necessary when you want to remove a user from a particular group. Removing a user from a group revokes any associated privileges or access they had.

Explanation:

• gpasswd: The command name.
• -d: Specifies that we want to remove a user from a group.
• user: The username of the user to be removed.
• group: The name of the group from which the user should be removed.

Example output:

Removing user from the group 'group'...

Conclusion

The gpasswd command is a powerful tool for managing group administration on Linux systems. Whether you need to define group administrators, set group members, create a group password, add users to groups, or remove users from groups, gpasswd provides a straightforward and efficient way to handle these tasks.