Undo an untar in the wrong place

tar tfz filename.tar.gz | xargs rm

This command is useful to delete the effects of accidental untarring into the wrong directory.

It works by passing the list of filenames from the stdout of the tar command into xargs, which in turn runs rm with the list of files as arguments. You could, of course, use it to run any command on all the filenames in a tar ball.