A simple function for Bash to recognize if there have been changes in a git repository's remote master compared to the local checked out branch.

changes_in_git_repo.sh

function changes_in_git_repo () {
  latestlocal=`git rev-parse HEAD`;
  echo $latestlocal
  gitrepourl=`git remote -v | grep fetch | awk '{print $2}'`;
  echo $gitrepourl;
  
  latestremote=`git ls-remote --heads $gitrepourl master| awk '{print $1}'`;
  echo $latestremote;
  
  if [ $latestlocal != $latestremote ]
  then
    echo "Changes since last build!";
    return 1;
  else
    echo "No changes since last build";
    return 0;
  fi
}