diff --git a/sys/src/cmd/vdiff.c b/sys/src/cmd/vdiff.c
index c8e5a8c4e..d48f1741f 100644
--- a/sys/src/cmd/vdiff.c
+++ b/sys/src/cmd/vdiff.c
@@ -613,7 +613,7 @@ threadmain(int argc, char *argv[])
 	}ARGEND;
 
 	parse(0);
-	if(nblocks==0){
+	if(nblocks==1 && blocks[0]->nlines==0){
 		fprint(2, "no diff\n");
 		exits(nil);
 	}