Make ls more POSIX-like

bin/ls.py

@@ -3,8 +3,17 @@ import os
 def get_app_class(template):
     class App(template):
         def F_main(self):
-            for file in os.listdir(self.argv[1]):
+            if len(self.argv) == 1:
+                directory = "."
+            else:
+                directory = self.argv[1]
+
+            try:
+                for file in os.listdir(directory):
                     print(file)
+            except OSError as e:
+                print(str(e))
+
             self.exit()
 
     return App