Linux Administration ( part 2 ): creating/managing groups in Linux

2 min readApr 17, 2022

What are Groups:

Groups in Linux are used to manage users and provide them a set of privileged permissions for reading, writing, and executing. by default Linux already has some groups such as sudo cdrom floppy audio dip video plugdev netdev bluetooth lpadmin scanner

Checking all groups of which a user is a member

we can use the following commands to do this:

$ groups username

hackpeas, Viraj Vaishnav, veer1024, Viraj1024

/etc/group

This particular file contains information regarding different groups and their members, and each line is written in the following format:

GROUP_NAME:x(WHICH_REPRESENT_PASSWORD_WHICH_IS_NULL):GROUP_ID:LIST_OF_ALL_GROUP_USERS_SEPARATED_BY_COMMA

GROUP_NAME:x(WHICH_REPRESENT_PASSWORD_WHICH_IS_NULL):GROUP_ID:ONE_USER_AND_FOR_OTHER_MEMBERS_OF_GROUP_SEPARATE_LINES_ARE_THERE

Creating new group

To create a group we can use groupadd command

$ groupadd [option] group_name

this command creates a new group with the name group_name, and also add its entry to /etc/group and /etc/gshadow

-> /etc/login.defs

whenever a new group is created, some of the default values are taken from this file

[options]

g integer ## to set specific GID
-K GID_MIN=1200 -K GID_MAX=1500 ## changing some default values from /etc/login.defs
-r ## use this to create a system group

$ groupadd -g 1005 grouptest