There are many instances where I had to replace some variable name in all my files. I use a small script to do this, Hope it helps you too.
Just remember to add it to a directory which is in the
$PATH. I have it in my
~/.scripts directory which is included in the
$PATH. Name it
git-sub and give it
executable permissions using
chmod +x ~/.scripts/git-sub. Now, you can just call
git sub old_var new_var
on terminal and it will do a global search and replace of all the files in the repository.