This gist is responsible for upgrading a system service (systemd) and going into the folder by it's specified user and performing a git pull. After the pull occures bring the service back up.

upgradeServicefolderByGit.sh

#! /bin/bash
set -o nounset
set -o errexit

if [[ $# -lt 3 ]]; then 
  echo "No arguments supplied."
  echo " Example: upgradeFoldByBash: [Service name] [service account] [folder]"
  exit 1
fi

SUDO="sudo -u ${2}"

pushd "${3}" >/dev/null

echo "Fetching updates."
${SUDO} git fetch

# only if we have updates to apply...
if [[ -n "$(${SUDO} git rev-list @{u}...)" ]]; then
  echo "Stopping the ${1} Service"
  systemctl stop ${1}

  echo "Performing the update."
  ${SUDO} git merge

  echo "Restarting the ${1} Service"
  systemctl start ${1}
else
  echo "No update needed."
fi

popd >/dev/null