github-add-fork

#!/bin/bash -eu

function usage()
{
	cat <<- EOF
	
	Usage: $0 <name of fork owner> [local name of remote]

	name of fork owner: name of the github user having the fork
	local name of remote: how to locally call the fork (defaults to name of fork owner)

	This script will add the given fork (by name of the owner) as a remote to your local clone
	
	EOF
	if [[ "$VERBOSE_USAGE" == "1" ]]
	then
		cat <<- EOF
		eg. Given you currently have this situation:
		$ git remote -v
		origin	https://github.com/someuser/somerepo.git (fetch)
		origin	https://github.com/someuser/somerepo.git (push)
	
		You can now add your own fork or anyone\'s fork:
		$ github-add-fork myusername
		Adding remote \'https://github.com/myusername/somerepo.git\' as \'myusername\':
		Updating myusername
		From https://github.com/myusername/somerepo
		[...]
		$ git remote -v
		origin	https://github.com/someuser/somerepo.git (fetch)
		origin	https://github.com/someuser/somerepo.git (push)
		myusername	https://github.com/myusername/somerepo.git (fetch)
		myusername	https://github.com/myusername/somerepo.git (push)
		EOF
	fi
}

FORK_REPO_OWNER=${1:-%ERROR%}
NAME_OF_FORK_OWNER=${2:-$FORK_REPO_OWNER}

if [[ "$FORK_REPO_OWNER" == "%ERROR%" ]]
then
	VERBOSE_USAGE=1
	usage
	exit 0
fi

CURRENT_REPO=$(git remote show -n origin | grep -w 'Fetch URL:' | awk -F': ' '{print $2}')
CURRENT_REPO_OWNER=$(echo "$CURRENT_REPO" | awk -F/ "{print \$4}")

if [[ -z "$CURRENT_REPO_OWNER" ]]
then
	usage
	echo "This repository has no origin (or this is not a repository)."
	exit 1
fi

FORK_REPO=$(echo "$CURRENT_REPO" | sed "s%/$CURRENT_REPO_OWNER/%/$FORK_REPO_OWNER/%")

if git remote | grep -q "^$NAME_OF_FORK_OWNER$"
then
	usage
	echo "Local name ('$NAME_OF_FORK_OWNER') already exists:"
	git remote show -n "$NAME_OF_FORK_OWNER"
	exit 1
fi


echo "Adding remote '$FORK_REPO' as '$NAME_OF_FORK_OWNER':"
git remote add -f "$NAME_OF_FORK_OWNER"  "$FORK_REPO"