How does the `git unstage` command affect changes staged for commit?

The git unstage command (more commonly used as git reset HEAD <file>) removes changes from the index (staging area), meaning it unprepares the changes for commit, but the changes in the working directory remain.

This is useful if you accidentally added files or changes to the index that you do not want to include in the next commit.

Example:

git add file.txt      # added the file to the index
# ... realized you don't want to commit file.txt

git reset HEAD file.txt  # remove file.txt from the index

After this, file.txt will remain modified in the working directory but will not be included in the commit until you add it back to the index.