Linux command- Get list of users in Ubuntu (v. 12.04 LTS). Open a terminal and type this command –
$ cat /etc/passwd
Also you can use these commands to view the output as pagewise
$ less /etc/passwd
$ more /etc/passwd”
- All fields are separated by colon (:) symbol.
- Total 7 fields exists.
- The first field is username, when user logs in. 1 to 32 characters in length
Output –
root:x:0:0:root:/root:/bin/bash
daemon:x:1:1:daemon:/usr/sbin:/bin/sh
bin:x:2:2:bin:/bin:/bin/sh
sys:x:3:3:sys:/dev:/bin/sh
sync:x:4:65534:sync:/bin:/bin/sync
……………………………………………………
bikram:x:1000:1000:Sunanda Ubuntu,,,:/home/bikram:/bin/bash
mysql:x:999:999::/home/mysql:/bin/sh
guest-bF03gb:x:115:125:Guest,,,:/tmp/guest-bF03gb:/bin/bash
guest-Oi8Hsz:x:116:126:Guest,,,:/tmp/guest-Oi8Hsz:/bin/bash
guest-Y2zQPI:x:117:127:Guest,,,:/tmp/guest-Y2zQPI:/bin/bash
Get only the usernames by using the AWK command, type these command in terminal :
$ awk -F’:’ ‘{ print $1}’ /etc/passwd
Change user in Terminal or console:
su command
$ su : allows you to become a super user / substitute user / spoof user / set user / switch user account. It allows a Linux user to change the current user account associated with the running terminal /console / shell. You must know the target user’s password. (How to set the root user’s password in Ubuntu)
$ su - $ su - username$ su - root$ su - bikram
You can also run commands as Root User-
su - root -c "ls -l /root"
A good reference article is here
Sudo command
- Configuration file name ‘/etc/sudoers’.
- Unlike su, sudo authenticates users against their own password rather than that of the target user.
- sudo command allows a system admin to grant authority to certain users (or groups of users) the ability to run some (or all) commands as root or another user.
gksu : GUI for su and sudo
gksu [-u <user>] [options] <command>
gksudo [-u <user>] [options] <command>
gksu -u root 'ls /root'