Killing application process in linux

As a Linux user, sometimes you need to terminate some application or process. There are many reason to kill application:

1) To quickly reclaim memory.
2) To kill suspicious process that may harm your system.
3) or to simply get rid of hanged program that out of your control.

To kill a program, you need to know current running program with their process number.

Use one of the following command to obtain much more complete information about the processes currently on the system:

$ps -aux | less

-a : switch is used to list the processes of all users on the system.
-u : switch is used to provide detailed information about each process running.
-x : switch is for the list processes to add that have no controlling terminal such as process run during the boot process.
less : This command is used to view output one screen at a time if list of processes can be quite long and occupy more than a single screen.

Now, you have the list of process with process id. Note the process number of the which you need to shutdown and fire the kill command below in terminal.

$ kill -9 2062

Switch -9 used to kill the process forcefully.