The group concept in Linux is used to manage user permissions collectively, and there are several useful commands related to groups. Here’s a breakdown to help you understand and use them:
🧰 Key Linux Group Commands
👥 1. See Groups for Current User
groups
- Shows which groups you are a member of.
👤 2. See Groups for Another User
groups username
Example:
groups alice
📜 3. List All Groups on the System
getent group
or
cat /etc/group
➕ 4. Add a New Group
sudo groupadd groupname
Example:
sudo groupadd devteam
🧑🤝🧑 5. Add a User to a Group
sudo usermod -aG groupname username
⚠️ Make sure to use -aG (append to group), or you’ll overwrite existing group memberships.
Example:
sudo usermod -aG devteam alice
The user may need to log out and back in for changes to take effect.
❌ 6. Remove a User from a Group
This isn’t done directly with a simple command, but you can use:
sudo gpasswd -d username groupname
Example:
sudo gpasswd -d alice devteam
🔧 7. Change a File or Folder’s Group
sudo chgrp groupname filename
Example:
sudo chgrp devteam /var/www/html
📂 8. Change Group Ownership Recursively
sudo chgrp -R groupname /path/to/folder