Preface
Introduction
Practice Setup
Linux Architecture
Basic Commands
Basic file management or operations on file
User administration
Networking
Linux Interview Questions

 

 

Check Login History in Linux

How do you check the hostname or system name that you have logged into?

[rreddy@knoblab ~]$ hostname
knoblab.sys1

 

How can you check what user credentials that you have logged in?

We have many ways to figure out this,

[rreddy@knoblab ~]$ whoami
rreddy

 

We can also type “id” command on the terminal,

[rreddy@knoblab ~]$ id
uid=1000(rreddy) gid=1000(rreddy) groups=1000(rreddy)
context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

 

Apart from the above, we can also confirm from the terminal section,

[rreddy@knoblab ~]$

 

Highlighted in red color is the present user id that you have logged into, this will help as you might switch back and forth between different accounts.

 

Note: 

The above option might not be available in every shell.

 

How to confirm that you are a non-root user? Or root user?

[rreddy@knoblab ~]$

 

If that portion is “$” then it’s a non-root user account.

If that section is “#” symbol, then we can confirm that it’s a root user account.

 

Who is a root user in Linux/Unix systems?

The root user is an administration account and it will possess all access credentials on the server without any restrictions.

One can install, uninstall a software or modify it.

The root user can add a new user or modify account’s access levels or delete it etc.

 

Note: 

In organizations, when we are working as a team we generally denied from root permissions and alternative arrangements are made.

 

How to check which all other users have logged into system? And from which terminals?

[rreddy@knoblab ~]$ who
rreddy :0 2016-01-13 19:45 (:0)
rreddypts/1 2016-01-14 01:59 (:0)
rreddypts/2 2016-01-14 09:44 (192.168.0.101)

 

Here, I have logged in through virtual machine and first 2 rows represent that. The last row, represents the terminal connection from PUTTY. That’s why, we can see an IP address associated with it.

 

Topics Summary