Topics Summary








In this section, we will discussion about user group details.


User Group:

A group is a collection of users who can share similar files, privileges, and other system resources.

We can bring in users with same privileges and can manage them under one group. This practice makes managing thousands of users in an easy manner.

For example,

DevAPM groups of developers for APM applications

QAgrp →group of quality analysts in an organization.

Wasadm group of users for administering WAS application instances.



A user can be a member of more than one group.


The commands for group management are,

#groupadd--------To add the group
#groupmod-------To modify the group
#groupdel---------To delete the group


Creating a new group:

A group contains group name, group id and users belongs to that group.

#groupadd –g


Group id’s 0-499 are reserved.

System groups  0-99 

Daemon groups 100- 499 

500 - 60,000 min gid and max gid, that a Linux OS can allocate to newly created group.



# groupadd –g 500 dba


Similar to user name & uid, group name is for human reference and gid is for system unique reference.


How and where to check if group details exist are not? Why??

For example,

An organization is undergoing a team restructuring, then we might have to come up with some new groups changes which encompass new changes.



When creating a new user, if associated group is not created already then “useradd” command will create that group.


Modify a group information:

To change the group id the command is,

#groupmod –g


Complete example…with output….pls

 To change the group name the command is,

#groupmod –n


Complete example…with output….pls


Delete a group from Linux machine:

We need to keep things in mind, before deleting a group account.

List them here…