Lesson 8.3: Create, delete, and modify local groups and group memberships


Group

  • Group Entries File : /etc/group

Password File

  • Password Entries File : /etc/shadow

File Example

[root@sanjeeb ~]# grep sanjeeb /etc/passwd sanjeeb:x:1000:1000:Sanjeeb KC:/home/sanjeeb:/bin/bash [root@sanjeeb ~]# grep sanjeeb /etc/group sanjeeb:x:1000: [root@sanjeeb ~]# grep sanjeeb /etc/shadow sanjeeb:$6$8E/Bt1v3w03gU8O/$KAI7oPCnjbzZ8mhaHFGcIREWlaxzqNi1nxOg6cs5x09dGvciEZd8bSSiccWZUA5eBBQRRAzLg0cnp2FvtnZFV1::0:99999:7:::

Creating Local Groups

[root@sanjeeb ~]# groupadd friends [root@sanjeeb ~]# grep friends /etc/group friends:x:1006: # Creating group with id [root@sanjeeb ~]# groupadd -g 4000 family [root@sanjeeb ~]# grep family /etc/group family:x:4000:

Modifying Local Group

# Modifying group name [root@sanjeeb ~]# groupmod -n newfriends friends [root@sanjeeb ~]# grep friends /etc/group newfriends:x:1006: # Modifying group id [root@sanjeeb /]# groupmod -g 1009 manager [root@sanjeeb /]# grep manager /etc/group manager:x:1009:

Deleting Local group

[root@sanjeeb ~]# groupdel newfriends

Example of group

[root@sanjeeb ~]# groupadd sales [root@sanjeeb ~]# groupadd marketing [root@sanjeeb ~]# groupadd production [root@sanjeeb ~]# egrep '(sales|marketing|production)' /etc/group sales:x:1001: marketing:x:1002: production:x:1003: # To add user in group when creating user [root@sanjeeb ~]# useradd -G sales hanuman # To modify a user to add group [root@sanjeeb ~]# usermod -G marketing ram # To modify user in multiple groups [root@sanjeeb ~]# usermod -G marketing,sales,production bharat [root@sanjeeb ~]# egrep '(sales|marketing|production)' /etc/group sales:x:1001:hanuman,bharat marketing:x:1002:ram,bharat production:x:1003:bharat # To append a user in another group [root@sanjeeb ~]# usermod -aG sales ram [root@sanjeeb ~]# grep sales /etc/group sales:x:1001:hanuman,bharat,ram
All systems normal

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