Try this first:
git checkout master
(If you're on a different branch than master
, use the branch name there instead.)
If that doesn't work, try...
For a single file:
git checkout HEAD /path/to/file
For the entire repository working copy:
git reset --hard HEAD
And if that doesn't work, then you can look in the reflog to find your old head SHA and reset to that:
git reflog
git reset --hard <sha from reflog>
HEAD
is a name that always points to the latest commit in your current branch.