Git update hook example (poorly tested)

update

#!/bin/sh

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

function test_exif {
	local commit="$1" path="$2"
	echo "${path}" | egrep -iq '\.(jpe?g|png)$' || return 0

	if ! which exiftool >/dev/null 2>&1; then
		echo >&2 "ExifTool is not installed on the server"
		return 1
	fi

	if git show "${commit}:${path}" | exiftool - | egrep -q '^GPS'; then
		echo >&2 "${commit:0:8}:${path} seems to have GPS metadata"
		return 1
	fi

	return 0
}

IFS=$'\n'
errors=0
for commit in $( git show --format=format:%H --quiet ${oldrev}..${newrev} ); do
	for path in $( git diff --name-only ${commit}^..${commit} ); do

		test_exif ${commit} "${path}" || ((errors++))
	done
done

exit ${errors}