test helper script to print ctrl characters

t/bin/echo_ctrl_chars.rb

@@ -0,0 +1,12 @@
+#!/usr/bin/ruby
+
+for arg in ARGV
+  if arg =~ /^(\d+):(\d+)$/
+    a = Integer($1)
+    b = Integer($2)
+    for i in a...b
+      puts "--- %s --- %s ---" % ["^" + (i+64).chr, i.chr]
+    end
+  end
+end
+