groups and group management in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a group in Linux?

A group in Linux is a collection of users that share the same permissions. It helps manage access to files and resources easily by assigning rights to the group instead of individual users.

beginner

Which command shows the groups a user belongs to?

The groups command followed by a username shows all groups that user belongs to. For example, groups alice lists Alice's groups.

beginner

How do you add a new group in Linux?

Use the groupadd command followed by the group name. For example, sudo groupadd developers creates a new group called 'developers'.

intermediate

How can you add a user to an existing group?

Use the usermod -aG groupname username command. The -aG option appends the user to the group without removing them from other groups. Example: sudo usermod -aG developers alice.

intermediate

What file stores group information on a Linux system?

The /etc/group file stores all group information including group names, group IDs, and members. You can view it with cat /etc/group.

Which command creates a new group named 'testers'?

A groupadd testers

B addgroup testers

C newgroup testers

D creategroup testers

The correct command to create a new group is groupadd testers. Other options are incorrect commands.

How do you list all groups a user 'bob' belongs to?

A listgroups bob

B groups bob

C showgroups bob

D usergroups bob

The groups bob command lists all groups for user bob.

What does the command usermod -aG admins alice do?

A Creates a new user alice in admins group

B Removes alice from all groups except admins

C Deletes the admins group

D Adds user alice to the admins group without removing other groups

The -aG option appends alice to the admins group without removing her from other groups.

Where is group information stored on a Linux system?

A /etc/group

B /etc/passwd

C /etc/shadow

D /var/group

Group information is stored in the /etc/group file.

Which command shows the current user's groups?

A id

B whoami

C groups

D getent

Running groups without arguments shows the current user's groups.

Explain how to add a user to a group and why it is useful.

Think about how groups help share access and the command to add users.

Describe where Linux stores group information and how you can view it.

It's a text file that lists all groups on the system.