Xkill is one belonging to the X Window System utility that instructs the X server to close the connection to an X client hard, and therefore the client ( in most cases) " kill " to (English to kill ).
In a graphical user interface, that is, the X Window System, you usually ended programs by clicking on the close button in the title bar of the window that belongs to the program.
Grown Historically this button from the program xkill, the " graphical " kill. Using this mandatory aid program could terminate an X client where you clicked on the associated X Window him. This functionality is still found in some window managers, for example, the key combination Ctrl Alt Esc again, with which to end the responsible X client by clicking on its window at a unresponsive GUI.
Other user interfaces
Xkill is limited to the X Window System. However, other interfaces give the possibility to end a program hard. Microsoft Windows operating systems offer the Task Manager. Apple Mac OS X offers the Force Quit mechanism.