git pre-push hook script to prevent unintentional force pushs

pre-push

#!/bin/bash
remote="$1"
url="$2"

z40=0000000000000000000000000000000000000000

IFS=' '
while read local_ref local_sha remote_ref remote_sha
do
	if [ "$local_sha" = $z40 ]
	then
		echo "Delete of $remote $remote_ref forbidden. Pass --no-verify to ignore check."
		exit 1
	else
		if [ "$remote_sha" != $z40 ]
		then
			base=`git merge-base $remote_sha $local_sha`
			if [[ "${base}" != "${remote_sha}" ]]; then
				echo "Force update of $remote $remote_ref forbidden. Pass --no-verify to ignore check."
				exit 1
			fi
		fi
	fi
done

exit 0