7 Ways to Check Who Is Logged-In Linux System

As a system administrator, you have to check who is logged in the system before start working on issues when you have a team members in different location because sometimes more than one people may work on the same issue due to miss communication or business critical.

It will create an additional problem since both are working in same issue. Better we can check who is logged in the system and what they are doing to prevent an unwanted damage on system.

Most of the people use w command to get the live users list but in Linux we have a punch of utilities to get the same information with additional options.

Suggested Read : How To Track Successful And Failed Login Attempts In Linux

In this article we are going to show you, how to get current logged-in users in Linux with five different methods. Knowing more than one method may give you a weightage in some point of time.

Method 1 : W Command

W command Show who is logged on and what they are doing. It displays information about current users on the machine by reading the file /var/run/utmp, and their processes /proc.

w command output comes with header which displays system activity such as current time, system up time, how many users are currently logged on, and the system load averages for the past 1, 5, and 15 minutes.

w command contains the following values login user name, tty number, remote host, user’s login time, idle time, JCPU (time used by all processes attached to the tty), PCPU (time used by the current process), and what command user performing currently.

# w
 17:13:34 up  1:52,  1 user,  load average: 0.11, 0.18, 0.15
USER     TTY      FROM              [email protected]   IDLE   JCPU   PCPU WHAT
root     pts/0    203.99.204.108    15:22    6.00s  0.18s  0.00s w

Method 2 : Who Command

who command show information about users who are currently logged in. It uses /var/run/utmp & /var/log/wtmp files to get the details.

who command output contains the following values login user name, tty number, date & time, and remote host.

# who
root     pts/0        2017-05-31 15:22 (203.99.204.108)

Method 3 : Whoami Command

whoami command Print the user name associated with the current effective user ID. Same as id -un.

# whoami
root

id command Print user and group information for the specified username but we can add -un options with id command to get current logged in users.

# id -un
root

Method 4 : users Command

users command print the user names of users currently logged in to the current host. It uses /var/run/utmp & /var/log/wtmp files to get the details.

# users
root

Method 5 : last Command

last command show list of last logged in users by searching the data from /var/log/wtmp file. Also it shows system reboot information.

last command output contains login user name, tty number, remote host, date, login time, logout time, and total duration (working time).

# last
root     pts/0        203.99.204.108 Wed May 31 15:22   still logged in
reboot   system boot  3.5.0-54-generic Wed May 31 15:20 - 17:57  (02:37)

Method 6 : finger Command

Finger is a utility which allows users to see information about system users (login name, home directory, name, how long they’ve been logged in to the system, etc.).

Finger utility available in all major Linux distribution and doesn’t installed by default. Use distribution package manager to install finger on your system.

$ finger
Login     Name       Tty      Idle  Login Time   Office     Office Phone
magi      daygeek    tty7        7  Jun  1 16:05 (203.99.204.108)

Method 7 : Manual Way

Last but not least, we can get the list of logged in users on Linux machine through manual way by using less command, more command, head command with followed by the log file location.

User authentication logs are located @ /var/log/secure for RHEL based systems & /var/log/auth.log for Debian based systems.

$ head -5 /var/log/auth.log
Jun  1 16:05:01 daygeek CRON[1944]: pam_unix(cron:session): session opened for user root by (uid=0)
Jun  1 16:05:01 daygeek CRON[1944]: pam_unix(cron:session): session closed for user root
Jun  1 16:05:44 daygeek lightdm: pam_unix(lightdm-greeter:session): session closed for user lightdm
Jun  1 16:05:44 daygeek lightdm: pam_unix(lightdm:session): session opened for user magi by (uid=0)
Jun  1 16:05:44 daygeek systemd: pam_unix(systemd-user:session): session opened for user magi by (uid=0)

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