What happens when I kill a command with ctrl+c?

Question

Specifically, I ran a rm -R /my/dir by mistake on a unix box (ubuntu 10.04). When I realized the horror within a few seconds I quickly killed it with the Ctrl+C command. It now seems I haven't lost any data. Is this possible? What did really happen in the background?

Answer 1

Ctrl+C send SIGINT signal to the process.

Its default action is "Abnormal termination of the process" so basically pressing Ctrl+C You are interrupting running process

If you were fast enough (before process scanned you directory structure) rm shouldn't delete anything (or maybe not if there wasn't much files in it).

Answer 2

If /my/dir contains lots of directories and files, the initial scan might take a while and it's quite possible you managed to stop your command while it was still just reading the directory structure. Other than that, Ctrl+C does not provide you any undo capabilities.

Answer 3

You are lucky if you pressed Ctrl+C fast enough to not lose any file. How did you determine you did not lose any file?

Pressing Ctrl+C will interrupt the delete process and terminate it. So, you need to double-check your files/folders and restore any deleted files.

Answer 4

You were lucky. The process has received an SIGINT, which (usually) kills the process. If you have not lost any data it is because the rm command was still busy traversing the directory structure, because it has to start deleting files in leaf directories without further subdirectories.