Set group password,its use and check which group after newgrp command in linux
As per the title of my post it has 3 questions:
(1) How to set group password in Linux ?
(2) What is its use ?
(3) How to know you are using which group after using command newgrp ?
How to set group password in Linux
Follow the given below steps to set group password
Step 1: Either you can create a new group or use the existence group.
To create new group use below command.
groupadd group_name
for eg.
groupadd hr
Step 2: To set group password use below given command
gpasswd group_name
For eg.
gpasswd hr
How to use group passwd
To use the permission and privileges of group you can temporarily join the group by using its group password
User can temporarily join the group which has password already set by below given command
newgrp group_name
for eg.
newgrp hr
In below given example we will see, the user called john do not have read,write,execute permission in directory called /opt/testdir.
The ls -ld command shows it has ownership of joe and group is hr and permission is 770 means only owner joe and group hr have read write execute permission.
But user john can also “read write execute” only when it uses the newgrp command and give group password of hr group.
See the below given scenario, how the john will create a testfile after using newgrp command which he was earlier not able to do so
root@tuxworld:~# ls -ld /opt/testdir/ drwxrwx--- 2 joe hr 4096 Jul 31 01:12 /opt/testdir/ root@tuxworld:~# root@tuxworld:~# su -l john $ whoami john $ $ touch /opt/testdir/testfile touch: cannot touch `/opt/testdir/testfile': Permission denied $ $ newgrp hr Password: $ $ touch /opt/testdir/testfile $ ls -l /opt/testdir/testfile -rw-rw-r-- 1 john hr 0 Jul 31 02:00 /opt/testdir/testfile $ $ exit $ exit root@tuxworld:~#
Note: You can use this in other scenario above one was just an example
How to know you are using which group after using command newgrp
$ groups john $ newgrp hr Password: $ groups hr john $ id uid=1011(john) gid=1012(hr) groups=1011(john),1012(hr) $ groups hr john $ whoami john $ $ id john uid=1011(john) gid=1011(john) groups=1011(john) $ $ groups hr john $ exit $ exit
To describe about this query I will first start with example.
(A)In below command user name is john and I use the command whoami. By which I got to know the username which I login is john
(B)After this I use the command id john which shows the user john’s UID and GId by which I can also know which is its primary or supplementary GROUPS.(i.e john ,john [here group is also john])
(C)Then I use the command called groups now here you can see the output in which it shows hr group which was not earlier listed with id command.
(D) Hence to know which group you are using after newgrp command ,check with below given two commands
1: id username
2: groups
(E)Now in next step you can see in example, I typed two times exit command .
The first exit command is when it exit out from group called hr
And the Second exit command is when I am doing exit from shell of user john