RoelVdP

If the deletion has not been committed, the command below will restore the deleted file in the working tree.
$ git checkout -- <file>

You can get a list of all the deleted files in the working tree using the command below.
$ git ls-files --deleted


If the deletion has been committed, find the commit where it happened, then recover the file from this commit.
$ git rev-list -n 1 HEAD -- <file>
$ git checkout <commit>^ -- <file>