Phil Hord [off-list ref] writes:
I messed something up during a rebase in a moved file (probably
because I had rename detection turned off). So now I want to fix it.
I think I have the commit amended right, but to be sure I want to diff
the old file and the new file.
$ git diff newfile HEAD^:oldfile
fatal: Path 'oldfile' exists, but not 'oldfile'.
Did you mean 'HEAD^:oldfile' aka 'HEAD^:./oldfile'?
You can feed two blob object names to "git diff", but I do not think
there is any provision to compare a blob object and a file in the
working tree.