diff --git a/tools/mk_format_patch b/tools/mk_format_patch
index d34ecbf9e2..31ef26ca3b 100755
--- a/tools/mk_format_patch
+++ b/tools/mk_format_patch
@@ -214,7 +214,7 @@ then
 
 		# Remove non-existent patches if they have been renamed or are no longer applied.
 		$(cd $target
-			for pt in $(ls)
+			for pt in ./*.patch
 			do
 				if test ! -f $tmp_dir/$target_name/$pt;then rm $pt;fi
 			done
@@ -222,7 +222,7 @@ then
 
 		# Intelligent copying
 		$(cd $tmp_dir/$target_name
-			for pt in $(ls)
+			for pt in ./*.patch
 			do
 				ii_cp $pt $target/$pt
 			done