13 Groups

Understanding User Groups
- Every user belongs to at least one group, often named after the user.
- Groups help manage permissions for multiple users.
- groups command shows all groups a user belongs to.
Checking Group Memberships
- groups <username> lists a specific user’s groups.
- id <username> provides numeric group IDs (GIDs).
Managing User Groups
- sudo usermod -aG <group> <user> adds a user to a group.
- sudo gpasswd -d <user> <group> removes a user from a group.
- Users must log out and back in for group changes to take effect.
Viewing System Groups
- /etc/group file lists all groups and their members.
- cat /etc/group displays the group database.
Granting Sudo Access Through Groups
- Users in the sudo group can execute admin commands.
- sudo usermod -aG sudo <user> grants sudo privileges.
- Users must belong to a group listed in /etc/sudoers to run sudo commands.