+
+# Update meta file if appropriate.
+md5_new=$(md5sum "$3" | cut -d ' ' -f 1)
+md5_old=$(cat "$meta_file" | sed -n '3p')
+if [ ! "$md5_new" = "$md5_old" ]; then
+ new_date=$(date -u "+%s")
+ sed -i '1,2!d' "$meta_file"
+ echo "$md5_new" >> "$meta_file"
+ echo "$new_date" >> "$meta_file"
+fi