Index: .hooks/pre-commit.d/check_files
===================================================================
--- /dev/null
+++ .hooks/pre-commit.d/check_files
@@ -0,0 +1,31 @@
+#!/bin/sh
+#
+# Check that only standard files are added to a port
+#
+#    .*\.mk
+#    Makefile.*
+#    dist-info.*
+#    pkg-descr.*
+#    pkg-message.*
+#    pkg-plist.*
+#    pkg-post.*
+#
+
+newish_files=$(git diff --name-only --cached --diff-filter=ACR | grep -E '^[^/]+/[^/]+/[^/]+$' | grep -v '/files/' | grep -v '^\.')
+status=0
+if [ $? -eq 0 ] ; then
+	for newish_file in ${newish_files} ; do
+		category=$(echo "${newish_file}" | awk -F '/' '{print $1}')
+		port=$(echo "${newish_file}" | awk -F '/' '{print $2}')
+		file=$(echo "${newish_file}" | awk -F '/' '{print $3}')
+		valid=$(echo "${file}" | grep -q '((Makefile|pkg-descr|pkg-message|pkg-plist|pkg-post)(.*))|(.*\.mk)')
+		if [ $? -ne 0 ] ; then
+			echo "[pre-commit] ERROR: invalid file '${file}' in '${category}/${port}'"
+			status=1
+		fi
+	done
+fi
+if [ ${status} -eq 1 ] ; then
+	echo "             Consider moving non-standard files to files/ or force-ignore this hook."
+	exit 1
+fi