Handy script for generating a github "diff" url between two refs

README.md

Example:

$ github-diff origin/master 04ed4b
https://github.com/example/repo/compare/a418bcece3d540ad1d4864030635c2d4ae2628b3...04ed4b34bee0a2b2003f3744b772473a4c8b604b

Requires the commits to be available locally, so you might have to git fetch first.

github-diff.sh

#!/bin/bash

if [ $# -lt 2 -o $# -gt 3 ]; then
  echo "usage: $0 [<remote>] <fromref> <toref>"
  echo ".. where <remote> can be a remote name or url"
  exit 1
fi

if [ $# = 3 ]; then
  remote="$1"
  shift
else
  branch="`git symbolic-ref --short HEAD`"
  if [ ! "${branch}" ]; then
    echo "Could not figure out current branch"
    exit 2
  fi

  for key in branch.$branch.pushremote remote.pushdefault branch.$branch.remote ; do
    remote="`git config $key ||:`"
    [ "$remote" ] && break
  done
  if [ ! "$remote" ]; then
    remote=$(git remote | head -n 1)
    if [ ! "$remote" ]; then
      echo "No remotes found"
      exit 2
    fi
    echo "NOTE: Could not find upstream remote for local branch '$branch', using first remote '$remote' by default"
  fi
fi

case "$remote" in
  *:*)
    url="$remote"
    ;;
  *)
    url="$(git config remote.$remote.url)"
    if [ ! "$url" ]; then
      echo "ERROR: No such remote '$remote'"
      exit 2
    fi
    ;;
esac

case "$url" in
  http*)
    :
    ;;
  *.*:*)
    url="${url#git@}"
    url="${url%/}"
    url="${url%.git}"
    url="https://${url/://}"
    ;;
  *)
    echo "UNSUPPORTED '$url'"
    exit 3
esac

echo "${url%/}/compare/$(git rev-parse $1)...$(git rev-parse $2)"