@b0rk
- anything that makes me confident i can go back to an OK place if I mess up--history in Git, a backup, a way to rebuild the box i am hacking on from scratch

- a "dry run" way to see what a cmd will do without doing it, e.g. for a bash script with loops/expansions, echo the cmd instead of running it; for SQL, trying a DELETE as a SELECT, or trying it in an uncommitted transaction before committing