Questions about how to run a program or other operating system function when a given combination of keys is pressed.

are a combination of a small number of keys, often a single key in combination with Shift, Ctrl and/or Alt, that results in an action. The action depends on the context in which the is defined and executed. The action can include operating system tasks, launching of programs, executing menu entries within a program.

Single key are often called a hotkey or a . Keymaps in the X Windows System environment can be used to define keys otherwise not available on the keyboard and are implemented using its file ~/.XmodMap and the program xmodmap.

For a more expansive description read the Wikipedia article on keyboard shortcuts.