Commands for Group Management(Part-02)

 

Commands for Group Management

Second Part:

Now we will see about group admin tasks

We will create 5 users(user1, user2, user3, user4, user5) & 1 group(itbd-group)

[root@itbd ~]# useradd user1

[root@itbd ~]# useradd user2

[root@itbd ~]# useradd user3

[root@itbd ~]# useradd user4

[root@itbd ~]# useradd user5

         [root@itbd ~]# tail -n 5 /etc/passwd

          [root@itbd ~]# groupadd itbd-group

                   [root@itbd ~]# grep itbd-group /etc/group

Now, we will make user1 as an admin of itbd-group, so that user1 can add or remove other users into/from itbd-group. Until make as admin of a group, except root user, any user can not add/remove users of a group.Before making admin user1, he will not be able to add/remove any users to/from a group.See below

When we create a group, by default no admin is here of this group. 

Very important things are - our any group's password information, admin info are kept in gshadow file.See below image

Now, we will make 'user1' as an admin of  "itbd-group".

[root@itbd ~]# gpasswd   -A   user1    itbd-group

Now, if we login as user1, user1 will be able to add/remove any user to/from group.Let's see.

[root@itbd ~]# su - user1

[user1@itbd ~]$ gpasswd -a user2 itbd-group    ; [adding user - user2 by group admin user1]

[user1@itbd ~]$ gpasswd -d user2 itbd-group    ; [removing user - user2  by  group admin]

Now, we will discuss about " login into group"

   I will switch into "user1" account. and see his id. By default - user1 is a group member of user1.

Here, we are seeing the group id of "user1" account is "user1"

Now, user1 will login into group.But here are some issues.

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If group has no password:

     users(not member) without password   - not be able to login into group

     users(not member) with password        - not be able to login into group

     

     users(member) without password         - able to login into group 

     users(member) with password              - able to login into group

     

If group  has password:

    users(not member) without password    - able to login into group with group password

    users(not member) with password         - able to login into group with group password

     

     users(member) without password        - able to login into group 

     users(member) with password             - able to login into group

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In a nutshell we can say,

If users (with password/without password) are members of a group -

                              They will be able to login into group  without prompting password

If users (with password) are not  members of a group -

                              They will be able to login into group  without prompting password

If users (without password) are not  members of a group -

                              They will be not to able to login into group  without prompting password