How to Kill user tty/pts sessions on Linux Systems.
Unix login session can be killed remotely by sending a hangup signal (SIGHUP) to the process running the login session. In this How2, we will dig further into it and explain the command-line option to kill unwanted or unused or idle ttys.
First things first, back in the days user terminals were connected to computers' electromechanical teleprinters or teletypewriters (TeleTYpewriter, TTY), since then the name TTY has continued to be used as the name for the text-only console. The word tty stands for teletype terminals.
1- Check active users logged into the server with: w
In other to kill unwanted or unused or idle TTYs we need the PID (Process ID) of that particular terminal (TTY). We first need to check the current connections to the server using the w
command.
$ w
14:57:48 up 10 days, 4:03, 3 users, load average: 0.11, 0.11, 0.21
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
user1 pts/0 1xx.1xx.xx.xx 14:57 1.00s 0.4s 0.02s w
user2 pts/1 1xx.1xx.xx.xx 09:22 1.00s 0.6s 0.02s -zsh
user3 pts/2 1xx.1xx.xx.xx 06:19 1.00s 0.13s 0.02s -zsh
Here, as you can see there are three (3) tty connections to our server, pts/0, pts/2 and pts/3 where PTS stands for pseudo terminal slave. You can also see which processes are currently executing for those tty connections.
2- Get the PID (Process ID) of a connected terminal (TTY) with: ps -ft tty
We can use the Process Status ps
command to find out the process ID.
ps -ft tty
$ ps -ft pts/1
UID PID PPID C STIME TTY TIME CMD
user2 567221 567220 0 15:02 pts/1 00:00:00 -zsh
Here... #567221 is the process ID. We then use the kill
command to terminate that tty connection.
$ kill 567221
If the process doesn't gracefully terminate, you can forcefully kill it by sending a SIGKILL kill -9
$ kill -9 567221
Alternatively use:
Single command to kill tty connections.
We can also use the pkill
command along with the switch -t
to kill a tty connection forcefully.
$ pkill -9 -t pts/0
Commands
w
: show who is logged on and what they are doingwho
: show who is logged ontty
: show current users pseudo-terminalps -ft pts/1
: get the process ID for the pseudo-terminalpkill
: signal process based on name and other attributes
That's it!!
Thanks for reading, go ahead and kill them OFF.