diff --git a/edname.sh b/edname.sh
index ab5acd2..5a2ae7b 100755
--- a/edname.sh
+++ b/edname.sh
@@ -26,6 +26,10 @@ execute_rename() {
   command="$1"
 
   lines="$(cat .original.edname | wc -l)"
+  if [ "$lines" != "$(cat .rename.edname | wc -l)" ] ; then
+    echo "mismatch in number of lines! not continuing. make sure no lines are added or removed!"
+    exit 1
+  fi
   IFS=$'\n' read -rd '' -a src_lines < .original.edname
   IFS=$'\n' read -rd '' -a dest_lines < .rename.edname