How to force user logout in Linux

There may be times when you need to forcibly log out a user from your Linux system, such as during system maintenance or when dealing with a malicious or unauthorized user.

If you have physical access to the server, you can disconnect the network cable and restart the system. However, this might not be feasible if you're working on remote servers via SSH. In such cases, you can force a user logout by terminating the user's active processes.

1. Open the terminal.
2. Display a list of users currently logged in to the system.

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

3. Identify and list all processes associated with the user you want to force logout.

   $ 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

4. Terminate the user's terminal or other session processes.

   $ sudo kill 2249
   [sudo] password for user:

   bash is normally the process if the user is connected via SSH.

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

   $ sudo pkill -u shakir

6. Verify if the user is still logged in.

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

7. ForceIf necessary, force the termination of any remaining processes associated with the user.

   $ sudo pkill -9 -u shakir