neveragaindottech.github.io/_bin/pr-diff

#!/bin/bash

prnum=$1

base=$(git merge-base origin/master origin/pr/$prnum)
git diff --no-color --unified=0 --text --ignore-all-space $base origin/pr/$prnum \
    | grep -v '^--- ' | grep -v '^+++ ' | grep --color=never '^[-+]'