Git update hook script that only accepts the push if all php files updated or added are complient with PSR2

phpcs-update-hook

#!/bin/sh
#
# Update hook script that only accepts the push if all php files updated or
# added are complient with PSR2
# --- Command line

refname="$1"
oldrev="$2"
newrev="$3"

phpcs="/usr/local/bin/phpcs"

if [ -z "$refname" -o -z "$oldrev" -o -z "$newrev" ]; then
	echo "usage: $0 <ref> <oldrev> <newrev>" >&2
	exit 1
fi

RET=0
for filename in $(git diff-tree --diff-filter=ACMRTUXB --name-only -r $oldrev..$newrev | grep "\.php$")
do
    echo "Processing file $filename"
    git show $newrev:$filename | $phpcs --standard=PSR2
    if [ 0 != $? ]
    then
        RET=1
    fi
done

exit $RET