LinuxQuestions.org - [SOLVED] How to login in from separate terminals in same OS instance?

CentOs 7

I used su to login as root.
I created several accounts,e.g. a1, b1, c1

Then I created two groups, gp1, gp2, and a directory, test
with owner a1, and group as gp1.

Then I added gp1 to a1.
Now I like to test permissions via
login on 3 terminals for a1, b1, and c1.

But whenever I am in root and did this:

Code:

[root@localhost ~]# login a1

The terminal closed immediately.

And when in another user account with admin privileges,
I do not get prompted for password.
Nothing happens.
the prompt just returns.... like so:

Code:

[user1@localhost ~]$ login a1

[user1@localhost ~]$

Here are the created accounts:

Code:

... ...

user1:x:1000:1000:user1:/home/user1:/bin/bash

a1:x:1001:1001::/home/a1:/bin/bash

b1:x:1002:1002::/home/b1:/bin/bash

c1:x:1003:1003::/home/c1:/bin/bash

I am able to login to another account if I logged off from current account. But this does not allow me to test permissions quickly!

How to login in from separate terminals in same OS instance?
Meaning all login accounts are active (not log-off), and I can easily switch between them via the terminals.

Thank you.