diff against the working directory with git-latexdiff

Do not ever use "sudo" for any task that creates file in your home directory. "sudo" does not only gives you permissions to do more things, it also executes the command as a different user, so you will end up with files belonging to root on your account. This is not only useless, but actually harmful. Use sudo for administrative tasks (e.g. upgrade you LaTeX install), but not for daily work.

The command git-latexdiff -v --main file.tex hash1 -- just works for me. git-latexdiff does a temporary checkout in a directory with a unique name under /tmp/. Are you using the latest version of git-latexdiff?