How to add a user to a group in Linux

Groups in Linux provide a way to organize users, with each user being assigned a primary group while also having the option to be a member of multiple secondary groups. This structure allows for efficient management of system permissions and privileges, which can be assigned to both users and groups. Members of a group will then inherit the group’s privileges.

Manually configuring local users and groups by editing the /etc/passwd and /etc/group files is possible, but it can lead to system inaccessibility due to misconfiguration. To simplify the process and minimize risk, it’s recommended to use dedicated tools like usermod when adding users to groups.