How to force logout a user in Linux

In Linux, there are situations where you may need to forcibly log out a user. This can be necessary when performing system maintenance, addressing unauthorized access, or managing hung user sessions. The ability to forcefully end a session ensures you can maintain control over the system without requiring a full reboot or network disconnection.

When working on remote servers, especially through SSH, physical intervention like disconnecting cables is not feasible. In such scenarios, using command-line tools to terminate the user's active processes is a more efficient and controlled method. It allows for minimal disruption to the rest of the system.

Linux provides several commands to log out a user by ending their session or killing their processes. This process targets only the specific user's activities, ensuring that other users on the system are unaffected. Understanding how to execute these commands will allow you to enforce session terminations without risking system-wide issues.

1. Open the terminal on your Linux system.
2. Display the currently logged-in users.

   $ who
   user     :0           2021-01-23 16:23 (:0)
   shakir   pts/1        2021-01-23 16:31 (192.168.111.1)

3. Identify the user to log out.

   The username and terminal type (e.g., pts/1) will help you identify the user session.

4. List all processes associated with the user.

   $ ps -U shakir
       PID TTY          TIME CMD
      2086 ?        00:00:00 systemd
      2087 ?        00:00:00 (sd-pam)
      2093 ?        00:00:00 pulseaudio
      2097 ?        00:00:00 tracker-miner-f
      2106 ?        00:00:00 dbus-daemon
      2126 ?        00:00:00 gvfsd
      2135 ?        00:00:00 gvfsd-fuse
      2136 ?        00:00:00 gvfs-udisks2-vo
      2149 ?        00:00:00 gvfs-mtp-volume
      2153 ?        00:00:00 gvfs-goa-volume
      2157 ?        00:00:00 goa-daemon
      2177 ?        00:00:00 goa-identity-se
      2186 ?        00:00:00 gvfs-afc-volume
      2194 ?        00:00:00 gvfs-gphoto2-vo
      2248 ?        00:00:00 sshd
      2249 pts/1    00:00:00 bash

   Related: How to list processes by user and group in Linux

5. Terminate the specific session by killing the related processes.

   $ sudo kill 2249
   [sudo] password for user:

   bash is the user's shell session. Terminating this will log out the user.

6. Alternatively, end all processes owned by the user.

   $ sudo pkill -u shakir

7. If needed, force terminate any remaining processes.

   $ sudo pkill -9 -u shakir

8. Verify the user has been logged out.

   $ who
   user     :0           2021-01-23 16:23 (:0)