Once you start collaborating with other developer it's going to be important to know how to revert a single file to a certain commit. This need arises because you sometimes need to change files not related to you're pull request in order to test the feature you're working on. However, manually changing each line of code in those files back to their original state and doing a new commit can lead to a messy commit history. Reverting the file is a much cleaner what to handling it.
First you need to go to the shared repository on GitHub and find the file that you want to revert. Once you navigate to the file, right above the file you should see this:
On the right hand side you can see a 7 digit commit ID and a date. That is the commit ID for the most recent commit in which that file was modified. Either write this commit ID down, or copy it to your clipboard.
The next thing you need is the path to the file from the working directory. This part is easy because the path to the file is on the same GitHub screen where you found the commit ID for the file.
Above you can see the same screenshot from before, but this time I've underlined the file path. Notice I only underlined part of the path. The first directory listed is the working directory name, and will be the directory you're in when using this file path. Because of this, you only want the underlined portion.
All that is left is to revert the file. Once you've opened a terminal and changed to the working directory, you use
git checkout to revert the file. The format of the git command will look like this:
git checkout [commit ID] -- path/to/file
I know what you're thinking, "Wait a minute, I thought the whole point was to not create a new commit?" Well that's half true. We didn't want a new commit for the file we reverted. But once we revert the file, we need to commit that change. In this case, the change is a revert of a single file. This done with the standard commit command:
git commit -m 'commit message'
Then you can push that commit to the remote so that the version of your branch on GitHub matches your local version.
To revert a single file to a specific version do the following:
- Find the commit ID of the version of the file you want to revert to.
- Find the path to the file you want to revert from the working directory.
- In the terminal, change directories to the working directory.
git checkout [commit ID] -- path/to/fileand hit enter.
- Commit the change to the reverted file.