Bash script to migrate multiple projects into one Lerna monorepo (https://lernajs.io)

migrate-to-lerna.sh

#!/usr/bin/env bash

set -x
shopt -s extglob dotglob

cd "$HOME"
rm -rf "$HOME/TEMP_DIR"
mkdir "$HOME/TEMP_DIR"
cd "$HOME/TEMP_DIR"
git init

function clone_repo () {
  git clone "https://github.com/some-username/$1.git"
  cd "$1"
  mkdir -p "packages/$1"
  git mv !(packages|.git|..|.) packages
  cd packages
  git mv !("$1") "$1"
  cd "$HOME/TEMP_DIR/$1"
  git add . -A
  git commit -m "Move source to packages/$1" -n
  cd "$HOME/TEMP_DIR"
}

clone_repo "some-package-1"
clone_repo "some-package-2"
clone_repo "some-package-3"

cd "$HOME/TEMP_DIR"
mkdir lerna-monorepo
cd lerna-monorepo
git init

git pull $HOME/TEMP_DIR/some-package-1 master --allow-unrelated-histories -s resolve
git pull $HOME/TEMP_DIR/some-package-2 master --allow-unrelated-histories -s resolve
git pull $HOME/TEMP_DIR/some-package-3 master --allow-unrelated-histories -s resolve

set +x
shopt -u extglob dotglob

Migrate multiple projects into one Lerna Monorepo

It's easy to run into conflicts because files which likely appear in all repos (such as package.json) can result in conflicts. Git sees those files moved from the root to packages/ many times and doesn't know what you want to do.

So you first need to move the source down into packages/ and commit it in each of the imported repos then git pull them into the new monorepo afterwards.

The merge strategy of resolve is important to help avoid conflicts, however if you see the error warning: no common commits then try again without it.

When you've run this script, run git remote add https://github.com/username/repo.git so you can git push it.

Any questions get me at https://twitter.com/fold_left as Gists don't notify you when someone comments on a Gist.

Thank you for your script. It didn't work out of the box for me... I had to remove master for the git pull part:

git pull $HOME/TEMP_DIR/some-package-1 master --allow-unrelated-histories -s resolve