How to undo a git commit without losing my files? [duplicate]

Question

Here's something that regularly happens to me at work:

[user@macmini ~/code/project $] git add .
[user@macmini ~/code/project $] git commit -m "Fixed whatever bug"
[master 93a3c47] Fixed whatever bug
 3 files changed, 290 insertions(+)
 create mode 100644 .DS_Store
 create mode 100755 some-code.js
 create mode 100755 some-other-code.js

As you can see, I've accidentally committed the .DS_Store file which macOS like creating after you open a folder in Finder.

In this case I usually clone the repo again, copy and paste my new code in, and commit again without the .DS_Store. But I know it's not the clean way to do it.

So, how can I cleanly undo a commit? I've tried git reset --hard HEAD but it deletes my new files too.

Answer 1

git reset HEAD~1

This will "undo" your last commit without touching your working directory (any our files). It is the same as git reset --mixed HEAD~1. You can also do git reset --soft HEAD~1, which will leave all the files as marked for commit.

If you mostly like your commit, but just want to make a small change to its content or its commit message, you can amend the current commit instead:

git rm .DS_Store
git commit --amend

This will prompt you for editing the commit message (you may leave it unchanged), and will then modify the commit with your changes.

---

git reset basically means "move my current branch to the given commit", and HEAD~1 means "the previous commit". The only problem with your command was that it included --hard, which says "oh, also make all my files look like they did in that commit".

A branch is just a label that references a particular commit; it can be freely moved around (although if you've pushed a branch and you move it backwards, you'll get problems when you try to push or pull).

If you ever feel the need to re-clone a repository, there is almost always a better solution in git. Commits in git, and the files in them can be undone, redone, moved, and sometimes even resurrected. Also, commits are local: no one sees them until you've pushed.