The ‘end task’ procedure for Linux

In our previous article – Sharpen your Linux vocabulary – we visualized few commonly used terms in context with the Linux operating system and its surroundings! I thank and appreciate the readers for adding on a few more words.

While I was figuring out a way to run Internet using a CDMA wireless modem on my Linux machine, one of the applications refused to respond due to some rare error. This very incident reminded me to come up with following article which elaborates few methods to help you terminate a process or application running on a Linux distribution - something similar to ‘end task’ on a windows operating system.

Remember, there is no Ctrl + Alt + Del key combination on Linux - by default!

Let us now see some of the interesting ways to kill those stuck and stubborn processes. A very mundane and primitive way is to use the command ps aux, look through the process list until you find the PID (process ID) you want and issue the kill command.

Alternatively, a better way is to use the ‘killall’ command which would automatically kill a program based on its name.

# killall mozilla-bin

There may be times when you shall only know a part of the name. In such a scenario, you can combine ps with grep, kill and awk to produce something like this.

# ps aux | grep mozilla | awk '{print $2}' | xargs kill

Now if that was tedious, there are still simpler ways. Enter pkill and the closely related pgrep. All these commands are part of the sys-apps/procps package and are specifically designed to search for or kill running processes. The previous command could be replaced with the following:

# pkill mozilla

If you just need to list the PID’s instead of killing them, you may just use pgrep.

Lastly, if you have a runaway process hogging /dev/dsp, or some other file or socket, you can use fuser, which displays the PID’s of process using a specified file or filesystem. You can give it the -k option and can easily kill those processes:

# fuser -k /dev/dsp

Now with the power of these commands, you shall never have the problem of ‘killing’ or stopping a process which you are unable to do otherwise.

Remember a fact that Linux has a lot of features which may not be evident by default or on the first look. But the depth it has considering the underlying architecture and a strong command line integration is simply superb. I would advise you to look out for a few HOW-TO’s, hang around in the IRC’s and participate in the discussions at various Linux forums - either as an audience or a contributor.

More than an operating system Linux is a large community and strong relationship between its members. A relationship of sharing knowledge and reusing it, unlike reinventing the wheel!