Server side Git update hook which rejects pushes without prior pulls from master

update

refname="$1"
oldrev="$2"
newrev="$3"
# Find out revision of master
masterref=`git show-ref --hash --heads master`
# Find out common merge base of master and the checked in revision.
mergebase=`git merge-base $masterref $newrev`
if [[ $mergebase != $masterref && ( $refname == *development* || $refname == *feature* ) ]]
then
        echo "Cannot push changes. Merge base is $mergebase, master is $masterref. Please type 'git pull origin master' and merge any conflicts first before$
        exit 1;
else
        exit 0;
fi