diff --git a/actioncable/lib/rails/generators/channel/channel_generator.rb b/actioncable/lib/rails/generators/channel/channel_generator.rb
index 6debe40c9117221aec7c9ca30df3c8ba3fa8eadd..d89ab458162b35d2c189653aef9f07c0c867cb9a 100644
--- a/actioncable/lib/rails/generators/channel/channel_generator.rb
+++ b/actioncable/lib/rails/generators/channel/channel_generator.rb
@@ -21,7 +21,7 @@ def create_channel_file
 
       protected
         def file_name
-          @_file_name ||= super.gsub(/\_channel/i, '')
+          @_file_name ||= super.gsub(/_channel/i, '')
         end
 
         # FIXME: Change these files to symlinks once RubyGems 2.5.0 is required.
diff --git a/actionmailer/lib/rails/generators/mailer/mailer_generator.rb b/actionmailer/lib/rails/generators/mailer/mailer_generator.rb
index 5a5c9d32bb6db4579fc48d38c3ec19efc9205387..ae5757917eedeb00bed269e0baefd7b1778c0cd4 100644
--- a/actionmailer/lib/rails/generators/mailer/mailer_generator.rb
+++ b/actionmailer/lib/rails/generators/mailer/mailer_generator.rb
@@ -15,7 +15,7 @@ def create_mailer_file
 
       protected
         def file_name
-          @_file_name ||= super.gsub(/\_mailer/i, '')
+          @_file_name ||= super.gsub(/_mailer/i, '')
         end
     end
   end
diff --git a/railties/lib/rails/generators/erb/mailer/mailer_generator.rb b/railties/lib/rails/generators/erb/mailer/mailer_generator.rb
index bc249aa5e553bb98a2277cf3d4e1f779c903073e..7f00943d80219c7d81d5ce623bf02a9cc6e5b326 100644
--- a/railties/lib/rails/generators/erb/mailer/mailer_generator.rb
+++ b/railties/lib/rails/generators/erb/mailer/mailer_generator.rb
@@ -26,7 +26,7 @@ def formats
       end
 
       def file_name
-        @_file_name ||= super.gsub(/\_mailer/i, '')
+        @_file_name ||= super.gsub(/_mailer/i, '')
       end
     end
   end
diff --git a/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb b/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb
index 343c8a394946c9279210a561b22418e0da5e7806..76a0b79654a2320bca3afc7f0401cde91cb6506d 100644
--- a/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb
+++ b/railties/lib/rails/generators/test_unit/mailer/mailer_generator.rb
@@ -19,7 +19,7 @@ def create_preview_files
 
       protected
         def file_name
-          @_file_name ||= super.gsub(/\_mailer/i, '')
+          @_file_name ||= super.gsub(/_mailer/i, '')
         end
     end
   end