Howto: Linux kill and logout users

by Vivek Gite · 19 comments

Yet another newbie question that suggests people love to kill and show their power to rest of the world ;)

There is a package called procps. It includes various useful (read as nifty) utilities. One of such utility is skill which is responsible to send a signal to users and process such as:

  • Halt user terminal
  • Kill user and logout

Also note that these are utilities to browse the /proc filesystem, which is not a real file system but a way for the kernel to provide information about the status of entries in its process table.

Task: How to halt/stop user called didi

Type the skill command as follows:
# skill -STOP -u didi

You muse be root to stop other users.

Task: How to resume already halted user called didi

Send CONT single to user didi, type the following command:
# skill -CONT -u didi

Task: How to kill and logout user called didi

You can send KILL single, type the following command:
# skill -KILL -u didi

Task: Kill and logout all users

The ultimate command to kill and logout all users, type the following command:
# skill -KILL -v /dev/pts/*

Please note that send users warning message or logout notice using wall command to avoid data loss.

Other useful nifty utilities provided by procps package

  • w : Show who is logged on and what they are doing
  • kill : Send signal to a process aka kill process
  • top : Display Linux tasks and other important stuff
  • vmstat : Display virtual memory statistics
  • free : Display free and used memory (RAM) statistics
  • slabtop : Display kernel slab cache information in real time

Featured Articles:

Want to read Linux tips and tricks, but don't have time to check our blog everyday? Subscribe to our daily email newsletter to make sure you don't miss a single tip/tricks. Subscribe to our weekly newsletter here!

{ 19 comments… read them below or add one }

1 max 08.15.06 at 8:48 am

This stuff is very cool!
I manage an iternet cafe linux-based and to log-out users remotely since now I first logged in the client machine via ssh and then export DISPLAY=:0 and kdeinit_shutdown.But doing that I was lucky with kde as default wm, while ’skill -KILL -u user’ is a better one_line command solution and for (I guess) all windows managers.
What I’m still wondering is: how to login remotely a user assuming that the default login manager is kdm?
Thanks in advance for any hint.

2 nixcraft 08.15.06 at 9:39 am

Hey max,

Great to know you are using Linux for your internet cafe.

skill should works with an wm or shell as it directly sends a signal to user.

>What I\’m still wondering is: how to login remotely a user assuming that the default login manager is kdm?

Sorry but I am not getting your question. Can you explain it little more?

3 max 08.15.06 at 12:01 pm

>Sorry but I am not getting your question. Can you explain it little more?
Well, when a customer finish his session is comfortable for me remotely close the session, but when I need to start a new one I need to sit-up from my chair and then go to the client and put the passwd (the user account is setted as default in kdm config) manually in the kdm welcome_login_window.
Now I’m just wondering how to put remotely the passwd in kdm to open the session again without (being lazy :-]) uprise from my chair?
I hope this wouldn’t be a too much tricky question an sorry about my english that isn’t my first language @^_^@

4 nixcraft 08.15.06 at 7:03 pm

Now, I understand your problem, you do not want go to each PC everytime new customer arrives. You can kill your customers session with skill but now you want to do auto login right from your own admin PC

Well I do not have exact solution but you can use KDE auto login facility to login the user automatically…

On the other hand, you may be writing some script, which will log them automatically

Another solution is kill user using skill
When new person comes for browsing just tell him to seat in front of computer
You login from your own admin pc to remote linux desktop system over ssh
And you type the command startx&
It will start the session on remove computer
In order to work this all system must boot to text mode
SSH should be running on all system
And autologin must be turned on for all linux system

Hope this helps

5 deivs 01.22.07 at 10:30 am

how to logout specified user after one hour automatically,how to do ?

6 nixcraft 01.22.07 at 3:11 pm

deivs.

You need to write a script. There is no inbuilt facility available, AFAK

7 Paul 05.15.07 at 7:54 pm

Hi,

I was pleased to see the skill inf have ld sessins n an LTSP server. I have since set a timeout uing TMOUT=7200 in /etc/profile.
Iuse skill -KILL -u paul to try and remove the old sessions. It succesfully removed one but doesn’t seem to remove the other 2 that are reported by ‘who’. Is it possible that ‘who’ is reprting stale/non-existant sessions?

8 vivek 05.16.07 at 9:46 am

Try to use pkill command
pkill -KILL -u username

9 Masood Yarmohammadi 05.27.07 at 3:39 pm

Hello,
i use
skill -KILL -u didi root

Now, i can’t login to ssh!

10 Hong@macau 07.18.07 at 9:34 am

i think when i enter this command
skill -KILL -u root

this will be kill all the process that create by root. such as ssh telnet process.

11 deivs 09.16.07 at 9:38 am

script to logout the users in the specific time

12 De.. 12.07.07 at 9:09 pm

i want to delete the process because my systems average load is too high 150.0 and more some time
and when i delete them ..they goes to and start increasing the load continously..
the process are perl scripts..
please help urgent

13 De.. 12.07.07 at 9:11 pm

the process hang up and when i shen them it shows like “defunction”

14 Terry 01.08.08 at 9:05 pm

Oops didn’t read through all the threads. I had a user who was logged on remotely as root but when I ran the command we were kicked out of our SSH sessions
Is there any way to recover SSH functionality short of rebooting

15 Anonymous 09.05.08 at 4:00 am

Only if you have another way of logging in (e.g. telnet, vnc, etc)

16 Afrizal 10.11.08 at 4:16 pm

Thank you for your shared knowledge.

Great info.

thanks,

zall

17 lee o 11.09.08 at 6:01 pm

Something for Linux Monty Python fans – one of you show a more funny way of kicking users off a linux box than THIS ONE HERE.. Very entertaining!

18 viper 12.06.08 at 7:46 am

how about to remove halt application..
at the bios I can’t find to solve that..
thanx…

19 kaminisuresh 02.26.10 at 11:05 am

hi
this is suresh i want which pc is having some server,how to identify which is having server

Leave a Comment

You can use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Previous post:

Next post: