Undo anything

Almost everything in git can be undone. The trick is knowing which undo fits: has the mistake been committed, and has it been pushed?

Goal#

Pick the right undo for each mistake, fix your last commit, and keep a secret out of history.

The undo map#

You want to undo	Command
changes to a file you have not staged	`git restore file`
staging a file (keep the changes)	`git restore --staged file`
the last commit's message or files	`git commit --amend`
the last commit, keeping its changes	`git reset --soft HEAD~1`
the last commit, and its changes	`git reset --hard HEAD~1`
a commit that is already pushed	`git revert <commit>`

git restore file and git reset --hard throw changes away for good, so run git status and git diff first. Everything else keeps your work.

The golden rule#

Rewrite only what you have not pushed. Amending or resetting changes commit hashes. If others already have the old commits, rewriting splits history between you. On your own branch, before review, rewrite freely. If you must push a rewrite of your own branch, use git push --force-with-lease, which refuses if someone else pushed in the meantime.

Secrets#

Committed a key or password? Removing the file in a new commit is not enough: it is still in history. If it was never pushed, rewrite the commit, as in this quest. If it was pushed, rotate the secret first: treat it as leaked, make a new one, and only then clean history. Then add the file to .gitignore, so it cannot happen again. AI agents read and write .env files too, which makes this mistake more common, not less.

Quest 07#

shell

quest start 7

The last commit has a typo in its message, "Add feeding schedul", and a secret in .env. It is not pushed. Fix it so there is still one commit, with the message Add feeding schedule, with feeding.txt and without .env. Then make sure .env is ignored. Then quest check.

Check it works#

git show --stat lists feeding.txt and .gitignore, not .env, under the right message.
quest check passes.

Exercise#

Make a throwaway commit, then try reset --soft, reset --mixed (the default) and reset --hard on it in turn. After each, run git status. Where did your change go each time?

More to try

git commit --amend --no-edit adds staged changes to the last commit without touching the message.
Look up git rm --cached. Why does the quest need it, when .gitignore alone does not help?

Quest 07

quest start 7
# ...fix it with real git...
quest check

Mark it done once quest check shows every line as PASS. Your progress stays in this browser.