git diff for custom 2 files outside of any repository?

Question

I need git diff functionality for 2 files that I have outside of any repository. Is there a way to do it? Something like git diff --file1 /path/file1.txt --fi

Answer 1

The answer is right in the git diff documentation (though I admit it's easy to miss):

git diff [] --no-index [--]

This form is to compare the given two paths on the filesystem. You can omit the --no-index option when running the command in a working tree controlled by Git and at least one of the paths points outside the working tree, or when running the command outside a working tree controlled by Git.

Your case might fall into the "--no-index is optional" category, but even if it's optional you can still use it, so:

git diff --no-index /path/file1.txt /path/file2.txt

will use Git's diff.