Merge multiple repos into a monorepo

create_monorepo.sh

# Reference: http://honnef.co/posts/2016/04/merging-git-repositories/

#!/bin/bash

base=baseUrl
projects=(project1 project2)
new_repo=agua

mkdir -p "$new_repo"
cd "$new_repo"
git init
git commit --allow-empty -m "Initial commit"
for prj in "${projects[@]}"; do
    git remote add "$prj" "$base/$prj"
    git fetch "$prj"
    git filter-branch -f --index-filter \
        'git ls-files -s | sed "s%\t\"*%&'"$prj"'/%" |
          GIT_INDEX_FILE=$GIT_INDEX_FILE.new git update-index --index-info &&
          mv "$GIT_INDEX_FILE.new" "$GIT_INDEX_FILE"' "$prj/master"
    git merge -m "Merge $prj" "$prj/master" --allow-unrelated-histories
    git remote rm "$prj"
done