How to undo git add before first commit

Normally I undo git add somefile with git reset somefile. However, if you’re before the first commit, this won’t work:

$ git reset somefile
fatal: Failed to resolve 'HEAD' as a valid ref.

The solution:

$ git rm --cached somefile
rm 'somefile'
$ git status -s somefile
?? somefile

How to undo git add before first commit —28 December 2013