tool for merging git upstream

merge-upstream.sh

#!/bin/bash

git status 1>/dev/null || exit 1

git fetch upstream
if [ "$?" != "0" ]; then
  echo >&2
  echo "fatal: no upstream remote configured" >&2

  ORIGIN=$(git remote -v | grep ^origin | cut -f2 | cut -f1 -d' ' | head -n 1)
  if [[ "$ORIGIN" =~ ^git@github\.com:(.*)/(.*)$ ]]; then
    REPO="${BASH_REMATCH[2]}"
    # nb. this uses https:// explicitly rather than git
    echo "  git remote add upstream https://github.com/OWNER/${REPO}" >&2
  fi
  exit 1
fi

CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
BRANCH="${1-$CURRENT_BRANCH}"

echo "merge: upstream/${BRANCH}"

git merge upstream/$BRANCH
if [ "$?" != "0" ]; then
  BASE=$(basename $0)
  echo "  use: $BASE branch_name" >&2
fi