How to modify existing, unpushed commits?

Question

I wrote the wrong thing in a commit message. Alternatively, I've forgotten to include some files.

How can I change the commit message/files? The commit has not been pushed yet.

Answer 1

If it's your last commit, just amend the commit:

git commit --amend -o -m "New commit message"

(using the -o (--only) flag to make sure you change only the commit message)

If it's a buried commit, use the awesome interactive rebase:

git rebase -i @~9   # Show the last 9 commits in a text editor

Find the commit you want, change pick to r (reword), and save and close the file. Done!

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Miniature vim tutorial (or, how to rebase with only 8 keystrokes 3jcwrEscZZ):

• Run vimtutor if you have time
• hjkl correspond to movement keys ←↓↑→
• All commands can be prefixed with a "range", e.g. 3j moves down 3 lines
• i to enter insert mode — text you type will appear in the file
• Esc or Ctrlc to exit insert mode and return to "normal" mode
• u to undo
• Ctrlr to redo
• dd, dw, dl to delete a line, word, or letter, respectively
• cc, cw, cl to change a line, word, or letter, respectively (same as ddi)
• yy, yw, yl to copy ("yank") a line, word, or letter, respectively
• p or P to paste after, or before current position, respectively
• :wEnter to save (write) a file
• :q!Enter to quit without saving
• :wqEnter or ZZ to save and quit

If you edit text a lot, then switch to the Dvorak keyboard layout, learn to touch-type, and learn vim. Is it worth the effort? Yes.

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ProTip™:   Don't be afraid to experiment with "dangerous" commands that rewrite history* — Git doesn't delete your commits for 90 days by default; you can find them in the reflog:

$ git reset @~3   # go back 3 commits
$ git reflog
c4f708b HEAD@{0}: reset: moving to @~3
2c52489 HEAD@{1}: commit: more changes
4a5246d HEAD@{2}: commit: make important changes
e8571e4 HEAD@{3}: commit: make some changes
... earlier commits ...
$ git reset 2c52489
... and you're back where you started

* Watch out for options like --hard and --force though — they can discard data.
* Also, don't rewrite history on any branches you're collaborating on.

Answer 2

I have added the alias of reci, recm for recommit (amend) it, now I can do it with git recm or git recm -m .

$ vim ~/.gitconfig

[alias]

    ......
    cm = commit
    reci = commit --amend
    recm = commit --amend
    ......

Answer 3

I realised that I had pushed a commit with a typo in it. In order to undo, I did the following:

git commit --amend -m "T-1000, advanced prototype"
git push --force

Warning: force pushing your changes will overwrite the remote branch with your local one. Make sure that you aren't going to be overwriting anything that you want to keep. Also be cautious about force pushing an amended (rewritten) commit if anyone else shares the branch with you, because they'll need to rewrite their own history if they have the old copy of the commit that you've just rewritten.