Reset vs. Revert vs. Checkout — Pick the Right Undo

Three Commands, Three Very Different Blast Radii

Command	What it does	Rewrites shared history?
git revert <commit>	Creates a new commit that undoes an old one	No — safe on main
git reset <commit>	Moves your branch pointer backward (optionally touching staged/working files too)	Yes — local/unshared only
git checkout -- <file> / git restore <file>	Discards uncommitted changes to a single file	N/A — working dir only

The Three Flavors of Reset

git reset --soft HEAD~1    # undo the commit, keep changes staged
git reset --mixed HEAD~1   # undo the commit AND unstage changes (default)
git reset --hard HEAD~1    # undo the commit AND discard the changes entirely

--hard is the only genuinely destructive one of the three — it throws away uncommitted work with no confirmation prompt. On a commit that's already been pushed and pulled by someone else, use revert instead of reset, because revert adds new history instead of erasing shared history out from under other people.