If you’ve launched a command from the shell running in the foreground, and want to kill it immediately, type ^C. The shell recognizes ^C as meaning, “terminate the current foreground command right now.” So if you are displaying a very long file (say, with the cat command) and want to stop, type ^C:

➜ cat bigfile
This is a very long file with many lines. Blah blah blah
blah blah blah blahblahblah ^C
➜

To kill a program running in the background, you can bring it into the foreground with fg and then type ^C. Alternatively, you can use the kill command (for more information, see Controlling Processes).

Killing a program is not a friendly way to end it. If the program has its own way to exit, use that when possible: see the sidebar for details.

^C works only within shells. It will likely have no effect if typed in a window that is not a shell window. Additionally, some programs are written to “catch” the ^C and ignore it: an example is the text editor Emacs.