more narrative on --example option feature

features/command_line/example_name_option.feature

@@ -1,7 +1,15 @@
 Feature: example name option
 
-  Use the --example (or -e) option to filter the examples
-  to be run by name.
+  Use the --example (or -e) option to filter the examples to be run by name.
+
+  The submitted argument is compiled to a Ruby Regexp, and matched against the
+  full description of the example, which is the concatenation of descriptions
+  of the group (including any nested groups) and the example.
+
+  This allows you to run a single uniquely named example, all examples with
+  similar names, all the example in a uniquely named group, etc, etc.
+
+  If no matches are found, then the entire suite is run.
 
   Background:
     Given a file named "first_spec.rb" with:
@@ -39,6 +47,10 @@ Feature: example name option
     When I run "spec . --example 'first .* first example'"
     Then the stdout should match "1 example, 0 failures"
 
+  Scenario: all examples in one group
+    When I run "spec . --example 'first group'"
+    Then the stdout should match "2 examples, 0 failures"
+
   Scenario: one match in one file with group name
     When I run "spec . --example 'second group first example'"
     Then the stdout should match "1 example, 0 failures"