It’s very easy to reset files that have not yet been committed to git.
Reset a single file
git reset <filename>
You can also specify the filename as the path to the file, like so:
git reset ./the/actual/relatvive/path/with/filename.ext
This will checkout the file from HEAD.
It is important to note that should you have a file that is the same name as a branch, you will need to rather run the following command:
git reset -- <filename>
Reset an entire branch
To reset an entire branch, you can reset it directly against the HEAD.
git reset --hard HEAD