Killing frozen applications in Ubuntu – Linux Hint

Sometimes applications that run on your system hang up and don’t respond anymore. A frozen application cannot be closed by simply pressing the x button in the top right corner of the interface, but restarting the system is not always a good solution – especially when the system is performing critical services.

Ubuntu has several methods to quickly and securely destroy frozen applications without rebooting the system: xkill, system monitoring utilities, and the kill, pkill and killall commands. In this article we discuss these methods on a machine with Ubuntu 20.04 LTS (Focal Fossa).


Xkill is a Linux utility that allows you to stop frozen applications running on Ubuntu. It is pre-installed in most Linux distributions, but if it is not installed on your system, you can install it as described below.

First open the terminal with Ctrl+Alt+Del and enter the following command:

$ sudo apt installation xorg-xkill

Then enter the sudo password. When prompted to confirm, press y and the equipment begins installing Xkill. Once the installation is complete, xkill can be used to destroy non-compliant applications.

To end the frozen request, type xkill into the terminal:

In this way your cursor X. Place an x on the request you want to close and click on it to close the request immediately.

You can create a key combination for xkill by right-clicking on the Ubuntu desktop and opening the Settings program.

In the settings window, in the left pane, touch the shortcut keys.

Then click on the + button on the right as shown in the figure below.

When the following dialog box appears, enter a user-friendly label name in the Name field. Then enter xkill in the Command field. Then click the Set Shortcut button to select a shortcut for the xkill utility.

Use any key combination to set up a shortcut to the xkill utility. For example, if you want to use Ctrl+k to start xkill, press and hold the key and then press the k key. Then release both buttons.

Click on the Add button to add a shortcut.

Now that you need to exit the frozen application, you can press the hotkeys to execute the xkill command.

Using the system monitor

You can also close the application from the Ubuntu system monitor. To open the system monitor, press the super key on the keyboard and enter the system monitor. When the system monitor icon appears, click the icon to open it.

The System Monitor application gives an overview of the processes running on the system. Select the process you want to complete and click the right mouse button. In the menu that appears, select Kill to end the selected process immediately.

Killing, killing and killing uses

Kill, pkill and killall can be called on the command line to kill an application based on its process name or process identification (PID).

To find the PID code, enter the following command into the terminal:

$ ps aux | grep

The next issue of 34636, for example, is the Rhythmbox PID application.

$ ps aux | grep rhythm box

To end a process with his PID, use the kill command as follows:

Here is 34636 the PID rhythm box obtained above.

You can also use the pkill and killall commands to end the process with his name. To use pkill to destroy a process, enter pkill and then the name of the process as follows:

To use killall to destroy a process, type killall and enter the name of the process as follows


As you can see, there are several ways to get out of a frozen application in Ubuntu. By using one of the above methods, you can easily terminate a request that does not respond and finish its work. In the same way, you can kill a request that has been blocked by another process.

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