git_clone_or_pull '<remote_path>' '<local_repo_dir>'

shared-functions

git_clone_or_pull() {
  local REPOSRC=$1
  local LOCALREPO=$2
  local LOCALREPO_VC_DIR=$LOCALREPO/.git
  if [ ! -d $LOCALREPO_VC_DIR ]; then
    git clone --recursive $REPOSRC $LOCALREPO
  else
    pushd $LOCALREPO
    git pull $REPOSRC && git submodule update --init --recursive
    popd
  fi
}