I pushed a commit to a repo where I accidentally added a file. Nobody else has merged from the remote repo so I can rewrite history. But when I remove file(unstage, not remove from source control, or disk) from local commit, I am unable to push changes. git push shows Everything up-to-date.

git checkout HEAD~ -- path/to/your/file
git add path/to/your/file
git commit --amend -C HEAD

The git checkout HEAD~ -- path/to/your/file command is used to restore a file from a previous commit in Git. Here’s how it works:

• git checkout is a command that allows you to switch to a different branch or commit in Git.
• HEAD~ refers to the parent commit of the current commit. So if you are currently on commit abc123, HEAD~ would refer to the commit before abc123.
• -- is used to separate the branch or commit name from the file path.
• path/to/your/file is the path to the file that you want to restore.

So when you run the git checkout HEAD~ -- path/to/your/file command, Git will restore the version of path/to/your/file that was in the parent commit (HEAD~). This will overwrite the current version of the file in your working directory with the previous version.

It’s important to note that this will discard any changes you’ve made to the file since the parent commit, so be sure to make a copy of the current version if you need to keep it.

The git commit --amend -C HEAD command is used to amend the previous commit in Git with the same commit message. Here’s how it works:

• git commit --amend is a command that allows you to modify the most recent commit in Git.
• -C HEAD is an option that allows you to reuse the commit message from the previous commit. HEAD refers to the current commit, so this option will use the commit message from the previous commit.

So when you run the git commit --amend -C HEAD command, Git will open your default text editor with the commit message from the previous commit simply save and exit the editor to use the same message.

After saving the commit message, Git will create a new commit object with the same changes as the previous commit, but with a new commit message (or the same message if you didn’t modify it).

It’s important to note that amending a commit changes its SHA-1 hash, which can cause problems if you have already pushed the original commit to a shared repository. If you’ve already pushed the commit, it’s generally best to avoid amending it to avoid causing problems for others who may have already based their work on the original commit.