Checkout from GitHub remote via `user:branch` syntax

gitco.sh

#!/bin/bash

# https://stackoverflow.com/a/26843249/995445
IFS=':' read -ra parts <<< "$1"
if [ ${#parts[@]} == 1 ]; then
	branch=${parts[0]}
else
	remote=${parts[0]}
	branch=${parts[1]}
fi

# https://stackoverflow.com/a/26843249/995445
if [[ -n $remote ]] && ! git config remote.${remote}.url > /dev/null; then
	url=$( git config remote.origin.url | sed -e "s#github\.com/[^/]*#github.com/"$remote"#g" )
	git remote add $remote $url
	git fetch $remote
fi

git checkout $branch