This is a minimal example to maintain a project that has numerous git repositories through the Google repo tool.
Make sure you have a bin/ directory in your home directory and that it is included in your path:
mkdir ~/bin
PATH=~/bin:$PATH
Download the Repo tool and ensure that it is executable:
curl https://storage.googleapis.com/git-repo-downloads/repo > ~/bin/repo
chmod a x ~/bin/repo
mkdir repo-lab-1
cd repo-lab-1
repo init -u https://github.com/passgat/repo-lab-1
repo sync