On Linux
git grep -l 'original_text' | xargs sed -i 's/original_text/new_text/g'
On Mac
git grep -l 'original_text' | xargs sed -i '' -e 's/original_text/new_text/g'
Background
I have tried many different ways of finding and replacing text. I have found this to be the most efficient and easiest to follow solution.