diff --git a/src/window.c b/src/window.c
index 3e32b37..3a68762 100644
--- a/src/window.c
+++ b/src/window.c
@@ -750,11 +750,10 @@
     size_t	bufsize,
     long	Prenum)
 {
-    size_t	len = STRLEN(cmd);
-
-    STRCPY(bufp, cmd);
     if (Prenum > 0)
-	vim_snprintf((char *)bufp + len, bufsize - len, "%ld", Prenum);
+	vim_snprintf((char *)bufp, bufsize, "%s %ld", cmd, Prenum);
+    else
+	STRCPY(bufp, cmd);
 }
 
 /*