Hard reset of a single file

I currently have three modified files in my working directory. However I want one of them to be reset to the HEAD status.

In SVN, I’d use svn revert <filename> (followed by svn update <filename> if needed) but in Git I should use git reset --hard. However this command cannot operate on a single file.

Is there any way in Git to discard the changes to a single file and overwrite it with a fresh HEAD copy?

You can use the following command:

git checkout HEAD -- my-file.txt

… which will update both the working copy of my-file.txt and its state in the index with that from HEAD.

-- basically means: treat every argument after this point as a file name. More details in this answer. Thanks to VonC for pointing this out.