diff --git a/lib/server/format.js b/lib/server/format.js
index 4b6c5983..44958d70 100644
--- a/lib/server/format.js
+++ b/lib/server/format.js
@@ -56,6 +56,7 @@
         this.permissions = {
             symbolic: function(perms) {
                 var type, owner, group, all,
+                    is              = typeof perms !== undefined,
                     permsStr        = '',
                     permissions     = '';
                 /*
@@ -70,7 +71,7 @@
                     S_IXOTH   0000001   executable by all
                 */
                 
-                if (perms) {
+                if (is) {
                     permsStr = perms.toString();
                     /* тип файла */
                     type = permsStr.charAt(0);