How to kill a process in linux (kali/ubuntu)

Managing processes is a fundamental skill for anyone using Linux. Knowing how to kill a process can be invaluable. In this blog post, we’ll explore various methods to terminate processes in Linux, for easy management of processes.

What is a Process?

In Linux, a process is an instance of a running program. Each process has a unique identifier known as the Process ID (PID). Sometimes, a process may become unresponsive or consume excessive resources, necessitating its termination.

Finding the Process ID (PID)

Before you can kill a process, you need to identify its PID. There are several commands you can use:

1. ps Command

The ps command displays information about running processes. You can filter the results to find a specific process.

ps aux | grep <process_name>

Replace <process_name> with the name of the process you’re looking for. The output will include the PID in the second column.

2. top Command

The top command provides a dynamic, real-time view of the running processes. To use it:

top

Once in top, you can see the list of processes along with their PIDs. To exit, press q.

3. pgrep Command

If you want to find the PID directly, you can use pgrep:

pgrep <process_name>

This command will return the PID(s) of the process(es) matching the name.

Killing a Process

Once you have the PID, you can terminate the process using one of the following methods:

1. kill Command

The simplest way to kill a process is with the kill command:

kill <PID>

Replace <PID> with the actual process ID. By default, kill sends the TERM signal, which requests the process to terminate gracefully.

2. kill -9 Command

If the process does not respond to the TERM signal, you can use the KILL signal, which forces termination:

kill -9 <PID>

Be cautious with this command, as it does not allow the process to clean up resources.

3. pkill Command

If you prefer to kill processes by name rather than PID, you can use pkill:

pkill <process_name>

This command will terminate all processes matching the specified name.

4. xkill Command

For graphical applications, xkill provides a user-friendly way to kill a window. Just run:

xkill

Your cursor will turn into a cross. Click on the window you want to close, and it will be terminated immediately.

Verifying Process Termination

After killing a process, it’s a good idea to verify it has been terminated. You can use the ps or pgrep command again:

ps aux | grep <process_name>

If the process no longer appears in the list, it has been successfully killed.

Conclusion

Killing a process in Linux is a straightforward task, but it’s essential to use the appropriate method based on the situation. Understanding how to find and terminate processes will help you maintain a responsive and efficient system. Always remember to try to gracefully terminate processes first before resorting to more forceful methods.