diff --git a/subcmds/list.py b/subcmds/list.py
index 961b195..00172f0 100644
--- a/subcmds/list.py
+++ b/subcmds/list.py
@@ -49,6 +49,10 @@
                  dest='path_only', action='store_true',
                  help="Display only the path of the repository")
 
+  def ValidateOptions(self, opt, args):
+    if opt.fullpath and opt.name_only:
+      self.OptionParser.error('cannot combine -f and -n')
+
   def Execute(self, opt, args):
     """List all projects and the associated directories.
 
@@ -60,11 +64,6 @@
       opt: The options.
       args: Positional args.  Can be a list of projects to list, or empty.
     """
-
-    if opt.fullpath and opt.name_only:
-      print('error: cannot combine -f and -n', file=sys.stderr)
-      sys.exit(1)
-
     if not opt.regex:
       projects = self.GetProjects(args, groups=opt.groups)
     else: