As a Linux user, you may sometimes find that one or more processes on your system are not behaving as expected. This could manifest as a program becoming unresponsive or consuming too many system resources, such as CPU, memory, or disk space. When this happens, you may need to stop the process to regain control of your system or free up resources for other applications.
In this tutorial, I will show you various ways to kill a process in Linux, focusing specifically on Ubuntu. I will discuss different methods for identifying the process to be killed, such as listing all running processes or searching for processes by name or pattern.
I will also show you different commands and techniques for killing a process gracefully or forcefully, as well as how to deal with stubborn processes that refuse to terminate.
By the end of this tutorial, you should have a good understanding of how to effectively manage processes in Ubuntu and how to kill them when necessary.
What Does Killing A Process Mean?
Killing a process in Linux means terminating it forcefully, using a command-line utility or graphical interface. It is important to note that killing a process should be done with care, as it can have unintended consequences.
For example, killing a process that is critical to the functioning of the system could cause the system to crash or become unstable. Therefore, it is crucial to identify the process accurately before attempting to kill it and to understand the potential consequences of doing so.
How To Identifying A Process In Ubuntu/Linux?
Identifying the process you want to terminate is an important step before killing it in Linux. Before you can kill a process, you need to be sure that you are targeting the correct process. The easiest way to do this is by listing all the processes running on your system.
To list all the running processes on your Ubuntu system, open up a terminal and type the following command:
ps aux
This will display a list of all running processes on your system, along with their process PIDs or Process IDs, CPU and Memory usage, and other details. Each process will have a unique PID assigned to it. This PID is used to identify the process you want to kill.
Once you have identified the process you want to terminate, take note of its PID. You will need this information to kill the process using the appropriate command. Be sure to double-check that you have the correct PID, as killing the wrong process can have unintended consequences and potentially harm your system.
If you want to filter the list of processes based on specific criteria, such as searching for a process by name or by a user, you can use other options with the ps command. For example, to list only the processes owned by the current user, you can use the following command:
ps -u $USER
This will display a list of processes owned by the current user, along with their PIDs and other details. You can modify this command with other options and filters to display a more specific list of processes. Try this command to know more.
ps --help all
How To Kill The Process In Ubuntu/Linux?
Once you have identified the process you want to terminate, you can use different commands and techniques to kill the process. The simplest and most common method is to use the kill command, followed by the process ID of the target process. For example, to kill a process with PID 1234, you can use the following command:
kill 1234
This will send a signal to the target process, asking it to terminate gracefully. The process will have a chance to save any data or perform cleanup tasks before exiting. If the process does not terminate within a certain timeframe, the system will send a stronger signal to force the process to terminate.
In some cases, a process may be unresponsive or stuck in an infinite loop, making it difficult to terminate using the kill command. In these cases, you can use the killall command to terminate all processes with a specific name or pattern. For example, to terminate all processes with the name ‘firefox‘, you can use the following command:
killall firefox
This will terminate all running instances of the Firefox browser. Be careful when using the killall command, as it can terminate multiple processes at once, potentially causing misbehaving system.
How To Deal With Stubborn Processes In Ubuntu/Linux?
Sometimes, you may encounter stubborn processes that refuse to terminate even after using the kill command or other termination techniques. These processes can be caused by a variety of factors, such as bugs, errors, or hardware issues. In these cases, you may need to use more advanced techniques to terminate the process.
One technique you can use is to send a signal to the process to dump its core. This can be done using the kill -6 command, which will cause the process to generate a core dump file that contains information about its state and memory usage at the time of termination.
This can be useful for debugging or troubleshooting purposes, but it will not necessarily terminate the process immediately. For example, to send a core dump signal to a process with PID 1234, you can use the following command:
kill -6 1234
If a process is still unresponsive after sending a core dump signal, you can try using the pkill command to send a signal to all processes with a specific name or pattern. This can be useful for terminating multiple instances of a process or related processes that are causing issues. For example, to send a ‘kill‘ signal to all processes with the name ‘firefox‘, you can use the following command:
pkill firefox
If none of these techniques work, you may need to resort to more drastic measures, such as rebooting the system or using the kill -9 command to forcefully terminate the process. However, be aware that these techniques can have unintended consequences, such as data loss or corruption, and should only be used as a last resort.
You can use the kill -9 command to send a stronger signal to force the process to terminate. This signal cannot be ignored by the process and will immediately terminate it, without giving it a chance to perform any cleanup tasks or save data.
For example, to force-kill a process with PID 1234, you can use the following command:
kill -9 1234
This should terminate the process immediately, but be aware that it can have unintended consequences, such as leaving behind temporary files or corrupting data.
In some cases, it may be necessary to investigate the root cause of the stubborn process and address it directly. This can involve debugging the process, checking system logs, or performing hardware diagnostics. It is important to approach this process with caution and only make changes or modifications that are well-understood and documented.
How To Kill A Process Using The System Monitor Tool In Ubuntu?
Ubuntu includes a graphical tool called System Monitor that can be used to monitor system performance and manage running processes. It is similar to Task Manager in Windows 10/11. This tool provides an easy-to-use interface for terminating processes, which can be useful for users who prefer a graphical interface over the command line.
To open the System Monitor tool in Ubuntu, you can click on the ‘Show Applications‘ from the dock and search for ‘System Monitor‘.
Alternatively, you can open the terminal and type the following command:
gnome-system-monitor
Once the System Monitor tool is open, go to the Processes tab and you will see a list of all running processes on your system. Each process is listed with its Process Name, User, ID (PID), CPU usage, Memory usage, and other Disk info. You can sort the list by clicking on the column headers to quickly find the process you want to terminate.
To terminate a process using the System Monitor tool, simply select the process you want to terminate and click on the ‘End Process‘ button in the toolbar.
You will be prompted to confirm the termination, and you can choose to terminate the process immediately or wait for it to finish gracefully.
If a process is unresponsive or stuck, you will be prompted to “Force Quit” it. This will send a stronger signal to the process, asking it to terminate immediately without performing any cleanup tasks or saving data.
Conclusion
Overall, killing a process in Linux involves using commands and techniques to terminate a target process. By using the kill, killall, or kill -9 commands, you can gracefully or forcefully terminate a process, depending on the circumstances. It is important to use these commands carefully and only target the correct processes, to avoid unintended consequences and potential harm to your system.
In this tutorial, I’ve shown you how to kill a process in Ubuntu using several different methods. It’s important to be cautious when using the kill command and to always make sure you’re terminating the correct process. With these commands in your toolkit, you should be able to free up system resources and terminate misbehaving applications with ease.
