[git] Unstage a deleted file in git

Both questions are answered in git status.

To unstage adding a new file use git rm --cached filename.ext

# Changes to be committed:
#   (use "git rm --cached <file>..." to unstage)
#
#   new file:   test

To unstage deleting a file use git reset HEAD filename.ext

# Changes to be committed:
#   (use "git reset HEAD <file>..." to unstage)
#
#   deleted:    test

In the other hand, git checkout -- never unstage, it just discards non-staged changes.