7 files changed, 7 insertions, 0 deletions
diff --git a/ext/tk/sample/tkextlib/vu/canvItems.rb b/ext/tk/sample/tkextlib/vu/canvItems.rb
index 364f87613b..aa9bd5e9f6 100644
--- a/ext/tk/sample/tkextlib/vu/canvItems.rb
+++ b/ext/tk/sample/tkextlib/vu/canvItems.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/charts'
diff --git a/ext/tk/sample/tkextlib/vu/canvSticker.rb b/ext/tk/sample/tkextlib/vu/canvSticker.rb
index 85713ebcf3..a240eb5be2 100644
--- a/ext/tk/sample/tkextlib/vu/canvSticker.rb
+++ b/ext/tk/sample/tkextlib/vu/canvSticker.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/charts'
diff --git a/ext/tk/sample/tkextlib/vu/canvSticker2.rb b/ext/tk/sample/tkextlib/vu/canvSticker2.rb
index 3d9495ffb0..5dec81aed9 100644
--- a/ext/tk/sample/tkextlib/vu/canvSticker2.rb
+++ b/ext/tk/sample/tkextlib/vu/canvSticker2.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/charts'
diff --git a/ext/tk/sample/tkextlib/vu/dial_demo.rb b/ext/tk/sample/tkextlib/vu/dial_demo.rb
index f1f2f110b1..409b8d73cf 100644
--- a/ext/tk/sample/tkextlib/vu/dial_demo.rb
+++ b/ext/tk/sample/tkextlib/vu/dial_demo.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/dial'
diff --git a/ext/tk/sample/tkextlib/vu/oscilloscope.rb b/ext/tk/sample/tkextlib/vu/oscilloscope.rb
index 1efe13ce01..0fa779985d 100644
--- a/ext/tk/sample/tkextlib/vu/oscilloscope.rb
+++ b/ext/tk/sample/tkextlib/vu/oscilloscope.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/charts'
diff --git a/ext/tk/sample/tkextlib/vu/pie.rb b/ext/tk/sample/tkextlib/vu/pie.rb
index c8f9276e4e..a61a19188e 100644
--- a/ext/tk/sample/tkextlib/vu/pie.rb
+++ b/ext/tk/sample/tkextlib/vu/pie.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu/pie'
diff --git a/ext/tk/sample/tkextlib/vu/vu_demo.rb b/ext/tk/sample/tkextlib/vu/vu_demo.rb
index 358d32495f..7b9741f933 100644
--- a/ext/tk/sample/tkextlib/vu/vu_demo.rb
+++ b/ext/tk/sample/tkextlib/vu/vu_demo.rb
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: false
 
 require 'tk'
 require 'tkextlib/vu'