[peff]

It's actually a little dangerous; what happens when you hit "^C" and the process dies before getting a chance to clean up? It's safer to do:

  some_cmd >foo.tmp && mv foo.tmp foo

The mv will do an atomic rename(), so that you either get the fully formed contents, or nothing at all.

[deafbybeheading]

Only if you interrupt the actual `rm`, no? If you interrupt the main command, you won't get a 0 exit code so the `||` branch still executes.

Your mechanism is clearly safer, but the user is required to clean up `foo.tmp` themselves in case of failure, so it's not really comparable.