How to merge multiple git repositories

mkglobalrepo.sh

#!/bin/bash

# This script merges several git repositories named experiment-<name>
# into a separate branch of a single repository.

mkdir global-repo
cd global-repo
git init
git remote add origin git@github.com:paoloambrosio/experiments.git
echo "Each experiment is committed in its own branch" >>README.txt
git add .
git commit -m 'Possibly the only commit on master'
for repo in wiremock-saboteur jmx-vs-agent dssim akka-http-auth packer sysintsim; do
  git remote add $repo git@github.com:paoloambrosio/experiment-$repo.git
  git fetch $repo
  git checkout -b $repo $repo/master  
done
git push --all origin