* How to add groups in linux
Adding users and groups in linux is very easy. But you need to know what you want to do.
Example: We are creating 3 groups and then add users to particular groups.
system marketing network
joel hardik
dbsolanki
krupesh sushil
drpanchal
* Add the linux groups to the server.
You can add groups in linux with "groupadd" command
[root@joel root]# groupadd system
[root@joel root]# groupadd marketing
[root@joel root]# groupadd network
* Now add linux users to their particular groups as we made up.
[root@joel root]# useradd -g system joel
[root@joel root]# useradd -g system krupesh
[root@joel root]# useradd -g marketing hardik
[root@joel root]# useradd -g marketing sushil
[root@joel root]# useradd -g network dbsolanki
[root@joel root]# useradd -g network krupesh
Here we have specify -g option. This parameter is for assinging users to particular groups.
If you simple add users without -g option then Redhat will create a group with same username and same groupname.
* How to change passwords
You can change the password with "passwd" command.
[root@joel root]# passwd joel
Changing password for user joel.
New password:
Retype password:
passwd: all authentication tokens updated sucessfully.
* Force users to change their passwords
You can force users to change their passwords the next time they log in with the passwd command's "-f" qualifier. Here we are doing that for user "hardik"
[root@joel root]# passwd -f hardik
Changing password for user hardik.
New password:
Retype password:
passwd: all authentication tokens updated sucessfully.
[root@joel root]#
* Setting a password expiry date
Password lifetimes can be set by using the passwd command's "-x" flag followed by the lifetime of the password in days. Once again we make the password of user "hardik" expire in 90 days.
[root@joel root]# passwd -x 90 hardik
Adjusting aging data for user hardik.
passwd: Sucess
[root@joel root]#
* Disable / Enable user accounts.
The passwd command is used again to this. The "-l" flag locks the account and the "-u" flag unlocks it.
Lock the Account
First lets lock the account of user "hardik"
[root@joel root]# passwd -l hardik
Locking password for user hardik.
passwd: Sucess
[root@joel root]#
Unlock the Account
[root@joel root]# passwd -u hardik
Unlocking password for user hardik.
passwd: Success.
* Delete users from system.
The userdel command is used. The "-r" flag removes all the contents of users's home directory.
[root@joel root]# userdel -r hardik
* Check which users belong to which groups
Use the "groups" command with username as the argument.
[root@joel root]# groups hardik
hardik : marketing
[root@joel root]#