Merge pull request #332 from eads/1.0.1

bail if not directory specified running tarbell generate, closes #289

tarbell/cli.py

@@ -116,7 +116,13 @@ def tarbell_generate(command, args, skip_args=False, extra_context=None, quiet=F
     with ensure_settings(command, args) as settings, ensure_project(command, args) as site:
         if not skip_args:
             output_root = list_get(args, 0, False)
-            is_folder = os.path.exists(output_root)
+            if output_root:
+                is_folder = os.path.exists(output_root)
+            else:
+                puts("\nYou must specify an output directory (e.g. `{0}`)".format(
+                    colored.cyan("tarbell generate _out")
+                ))
+                sys.exit()
         if quiet:
             site.quiet = True
         if not output_root: