Pre-Commit hook to check PHP for syntax error

pre-commit syntax check [PHP]

#!/bin/sh
#
# A hook to disallow php syntax errors to be committed
# by running php -l (lint) on them. It requires php-cli
# to be installed.
#
# Credits to https://github.com/phpbb/phpbb, https://raw.github.com/phpbb/phpbb/develop-olympus/git-tools/hooks/pre-commit
#
# This is a pre-commit hook.
#
# To install this you can either copy or symlink it to
# $GIT_DIR/hooks, example:
#
# ln -s ../../git-tools/hooks/pre-commit \\
#   .git/hooks/pre-commit

if [ -z "$PHP_BIN" ]
then
	PHP_BIN=php
fi

if [ "$(echo -e test)" = test ]
then
	echo_e="echo -e"
else
	echo_e="echo"
fi

# necessary check for initial commit
if git rev-parse --verify HEAD >/dev/null 2>&1
then
	against=HEAD
else
	# Initial commit: diff against an empty tree object
	against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

errors=""
if ! which "$PHP_BIN" >/dev/null 2>&1
then
	echo "PHP Syntax check failed:"
	echo "PHP binary does not exist or is not in path: $PHP_BIN"
	exit 1
fi

# dash does not support $'\n':
# http://forum.soft32.com/linux2/Bug-409179-DASH-Settings-IFS-work-properly-ftopict70039.html
IFS='
'
# get a list of staged files
for line in $(git diff-index --cached --full-index $against)
do
	# split needed values
	sha=$(echo $line | cut -d' ' -f4)
	temp=$(echo $line | cut -d' ' -f5)
	status=$(echo $temp | cut -d'	' -f1)
	filename=$(echo $temp | cut -d'	' -f2)

	# file extension
	ext=$(echo $filename | sed 's/^.*\.//')

	# only check files with php extension
	if [ $ext != "php" ]
	then
		continue
	fi

	# do not check deleted files
	if [ $status = "D" ]
	then
		continue
	fi

	# check the staged file content for syntax errors
	# using php -l (lint)
	result=$(git cat-file -p $sha | "$PHP_BIN" -n -l -ddisplay_errors\=1 -derror_reporting\=E_ALL -dlog_errrors\=0 2>&1)
	if [ $? -ne 0 ]
	then
		# Swap back in correct filenames
		errors=$(echo "$errors"; echo "$result" | grep ':' | sed -e "s@in - on@in $filename on@g")
	fi
done
unset IFS

if [ -n "$errors" ]
then
	echo "PHP Syntax check failed: "
	$echo_e "$errors"
	exit 1
fi