How to undo last commtis on GIT

If you have comitted wrong files to git and you want to undo it, here is what you can do :

$ git commit -m "Some comment here"                         (1)
$ git reset HEAD~                                           (2)
<< edit files as necessary >>                               (3)
$ git add ...                                               (4)
$ git commit -c ORIG_HEAD                                   (5)

1. This is what you are looking to undo
2. This leaves your working tree (the state of your files on disk) unchanged but undoes the commit and leaves the changes you committed unstaged (so they'll appear as "Changes not staged for commit" in git status and you'll need to add them again before committing). If you only want to add more changes to the previous commit, or change the commit message¹, you could use git reset --soft HEAD~ instead, which is like git reset HEAD~ but leaves your existing changes staged.
3. Make corrections to working tree files.
4. git add anything that you want to include in your new commit.
5. Commit the changes, reusing the old commit message. reset copied the old head to .git/ORIG_HEAD; commit with -c ORIG_HEAD will open an editor, which initially contains the log message from the old commit and allows you to edit it. If you do not need to edit the message, you could use the -C option

However, If you don't need to reset to an earlier commit if you just made a mistake in your commit message. The easier option is to git reset (to unstage any changes you've made since) and then git commit --amend, which will open your default commit message editor pre-populated with the last commit message.

Beware however that if you have added any new changes to the index, using commit --amend will add them to your previous commit.

Some Explaination:

Undoing a commit is a little scary if you don't know how it works. But it's actually amazingly easy if you do understand.

Say you have this, where C is your HEAD and (F) is the state of your files.

   (F)
A-B-C
    ↑
  master

You want to nuke commit C and never see it again. You do this:

git reset --hard HEAD~1

The result is:

 (F)
A-B
  ↑
master

Now B is the HEAD. Because you used --hard, your files are reset to their state at commit B.

Ah, but suppose commit C wasn't a disaster, but just a bit off. You want to undo the commit but keep your changes for a bit of editing before you do a better commit. Starting again from here, with C as your HEAD:

   (F)
A-B-C
    ↑
  master

You can do this, leaving off the --hard:

git reset HEAD~1

In this case the result is:

   (F)
A-B-C
  ↑
master

In both cases, HEAD is just a pointer to the latest commit. When you do a git reset HEAD~1, you tell Git to move the HEAD pointer back one commit. But (unless you use --hard) you leave your files as they were. So now git status shows the changes you had checked into C. You haven't lost a thing!

For the lightest touch, you can even undo your commit but leave your files and your index:

git reset --soft HEAD~1

This not only leaves your files alone, it even leaves your index alone. When you do git status, you'll see that the same files are in the index as before. In fact, right after this command, you could do git commit and you'd be redoing the same commit you just had.

One more thing: Suppose you destroy a commit as in the first example, but then discover you needed it after all? Tough luck, right?

Nope, there's still a way to get it back. Type git reflog and you'll see a list of (partial) commit shas that you've moved around in. Find the commit you destroyed, and do this:

git checkout -b someNewBranchName shaYouDestroyed

You've now resurrected that commit. Commits don't actually get destroyed in Git for some 90 days, so you can usually go back and rescue one you didn't mean to get rid of.

Another way of doing it can be following :

Add/remove files to get things the way you want:

git rm classdir
git add sourcedir

Then amend the commit:

git commit --amend

The previous, erroneous commit will be edited to reflect the new index state - in other words, it'll be like you never made the mistake in the first place.

Note that you should only do this if you haven't pushed yet. If you have pushed, then you'll just have to commit a fix normally.

Yet Another approach can be :

This took me a while to figure out, so maybe this will help someone...

There are two ways to "undo" your last commit, depending on whether or not you have already made your commit public (pushed to your remote repository):

How to undo a local commit

Lets say I committed locally, but now want to remove that commit.

git log
    commit 101: bad commit    # latest commit, this would be called 'HEAD'
    commit 100: good commit   # second to last commit, this is the one we want

To restore everything back to the way it was prior to the last commit, we need to reset to the commit before HEAD:

git reset --soft HEAD^     # use --soft if you want to keep your changes
git reset --hard HEAD^     # use --hard if you don't care about keeping the changes you made

Now git log will show that our last commit has been removed.

How to undo a public commit

If you have already made your commits public, you will want to create a new commit which will "revert" the changes you made in your previous commit (current HEAD).

git revert HEAD

Your changes will now be reverted and ready for you to commit:

git commit -m 'restoring the file I removed by accident'
git log
    commit 102: restoring the file I removed by accident
    commit 101: removing a file we dont need
    commit 100: adding a file that we need

For more info, check out Git Basics - Undoing Things