Lose a Commit, Get it Back
Learn how you can remove a commit and then retrieve it.
We'll cover the following
Add commits#
First, set up a repository with two commits:
1 mkdir lgthw_reflog
2 cd lgthw_reflog
3 git init
4 echo first commit > file1
5 git add file1
6 git commit -m "first commit"
7 echo second commit >> file1
8 git add file1
9 git commit -am 'second commit message for file1.1'
10 git log
Remove commit#
Then do some magic to effectively remove the last commit by entering the following commands in the terminal given above:
10 git checkout HEAD^
11 git branch -f master
12 git checkout master
13 git log
What was that?
Don’t worry about what you just did; it’s a more advanced set of commands that mess with Git’s history. We’ll cover it later.
The last commit has disappeared! You have fully reverted the master branch to where it was before. Even git log --all does not show it because it’s not on a branch.
Don’t worry about the details of what you did! The point here is to create a situation in Git that you want to get out of.
Retrieve commit#
This is where Git’s reflog can help.
Git reflog records all movements of branches in the repository. As with git stashes, it is local to your repository.
14 git reflog
Reflog?
The reflog is called that because it’s a “REFerence LOG”. I always think of someone being flogged, but that’s probably memories of painful Git experiences…
Git’s reflog is a history of the changes made to the HEAD (remember the HEAD is a pointer to the current location of the repository).
Use git reset to restore state#
If you git reset --hard the repository to the given reference (in this case, 40e99f7; your ID will differ!):
15 git reset --hard 40e99f7
16 git log
You are returned to where you were.
The --hard flag updates both the index (staging/added) and the working tree as you saw previously.
The reflog contains references to the state of the repository at various points, even if those points are no longer apparently reachable within the repository.
