Linux /etc/group file contents

/etc/group file

It stores group information or defines the user groups i.e. it defines the groups to which users belong. There is one entry per line, and each line has the following format (all fields are separated by a colon (:)

cdrom:x:24:vivek,student13,raj
_____ _  _  _____
|    |  |  |
|    |  |  |
1    2  3  4

Where,

1. group_name: It is the name of group. If you run ls -l command, you will see this name printed in the group field.
2. Password: Generally password is not used, hence it is empty/blank. It can store encrypted password. This is useful to implement privileged groups.
3. Group ID (GID): Each user must be assigned a group ID. You can see this number in your /etc/passwd file.
4. Group List: It is a list of user names of users who are members of the group. The user names, must be separated by commas.

More About User Groups

Users on Linux and UNIX systems are assigned to one or more groups for the following reasons:

• To share files or other resource with a small number of users
• Ease of user management
• Ease of user monitoring
• Group membership is perfect solution for large Linux (UNIX) installation.
• Group membership gives you or your user special access to files and directories or devices which are permitted to that group