easier way to use subtrees

subtree.sh

#!/bin/bash
set -e

REPOS="$(cat $(dirname $0)/.subtree)"


usage() {
  echo "usage: $(basename $0) <command>"
  echo "commands are: "
  echo "  init             sets up all remotes and subtrees locally"
  echo "                   this is required for any other actions"
  echo ""
  echo "  pull <ms|'all'>  pulls a specific ms, or all configured"
  echo "                   repos from master"
  echo ""
  echo "  push <ms|'all'>  pushes a specific ms, or all configured"
  echo "                   repos to master"
  exit 0
}



pull_repos() {
  selected_ms=${1:-'all'}

  if [[ $selected_ms == 'all' ]]; then
    repos=$REPOS
  else
    for ms in $selected_ms; do
      repos="$repos $(get_repo_from_ms $ms)"
    done
  fi

  # do pull of selected or all ms's
  for repo in $repos; do
    ms=$(get_ms_from_repo $repo)
    git subtree pull --squash --prefix=$ms/ $ms master
  done
}

push_repos() {
  ms=${@:-'all'}

  if [ $ms == 'all' ]; then
    ms=""
    for repo in $REPOS; do
      ms="$ms $(get_ms_from_repo $repo)"
    done
  else
    repos="$(get_repo_from_ms)"
  fi

  for m in $ms; do
    git subtree push --prefix=$m/ $m $(cd $m ; git rev-parse --abbrev-ref HEAD)
  done
}

init_repos() {
  for repo in $REPOS; do
    ms=$(get_ms_from_repo $repo)

    git remote add $ms $repo \
      && git subtree add --squash --prefix=$ms/ $ms master
  done
}


set_branch() {
  echo not done
}

get_ms_from_repo() {
  echo $(echo $1 | sed -E 's/.*\/([a-z]+).git/\1/')
}

get_repo_from_ms() {
  echo $(echo $REPOS | grep $1)
}




CMD=${1:-help}

cd $(dirname $0)

case $CMD in
  pull)
    shift
    pull_repos $@
    ;;
  init)
    shift
    init_repos $@
    ;;
  push)
    shift
    push_repos $@
    ;;
  setbranch)
    shift
    set_branch $@
    ;;
  *|help)
    usage
    ;;
esac