diff --git a/archive/r/ruby/rot13.rb b/archive/r/ruby/rot13.rb
new file mode 100644
index 000000000..6bedc091f
--- /dev/null
+++ b/archive/r/ruby/rot13.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+USAGE = "Usage: please provide a string to encrypt"
+
+def usage!
+  warn USAGE
+  exit 1
+end
+
+def rot13(str)
+  str.tr("A-Za-z", "N-ZA-Mn-za-m")
+end
+
+input = ARGV.first
+usage! if input.nil? || input.strip.empty?
+
+puts rot13(input)