depot_tools/git-nav-upstream

#!/usr/bin/env bash
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

if git rev-parse 2> /dev/null; then
  git checkout "$(git rev-parse  --abbrev-ref "@{u}")"
else
  echo "error: not in a git repository" >&2
  exit 1
fi