diff --git a/lib/n65/front_end.rb b/lib/n65/front_end.rb
index 4493cda..bc13130 100644
--- a/lib/n65/front_end.rb
+++ b/lib/n65/front_end.rb
@@ -1,73 +1,63 @@
+# frozen_string_literal: true
+
 require 'optparse'
 require_relative '../n65'
 
 module N65
-
-  ####
-  ##  This class handles the front end aspects,
-  ##  parsing the commandline options and running the assembler
+  # This class handles the front end aspects,
+  # parsing the commandline options and running the assembler
   class FrontEnd
-
-    ####
-    ##  Initialize with ARGV commandline
     def initialize(argv)
-      @options = {output_file: nil, write_symbol_table: false, quiet: false, cycle_count: false}
+      @options = { output_file: nil, write_symbol_table: false, quiet: false, cycle_count: false }
       @argv = argv.dup
     end
 
-
-    ####
-    ##  Run the assembler
+    # Run the assembler
     def run
-      ##  First use the option parser
       parser = create_option_parser
       parser.parse!(@argv)
 
-      ##  Whatever is leftover in argv the input files
       if @argv.size.zero?
-        STDERR.puts("No input files")
+        warn('No input files')
         exit(1)
       end
 
-      ##  Only can assemble one file at once for now
+      # Only can assemble one file at once for now
       if @argv.size != 1
-        STDERR.puts "Can only assemble one input file at once, but you can use .inc and .incbin directives"
+        warn('Can only assemble one input file at once, but you can use .inc and .incbin directives')
         exit(1)
       end
 
       input_file = @argv.shift
 
-      ##  Make sure the input file exists
-      unless File.exists?(input_file)
-        STDERR.puts "Input file #{input_file} does not exist"
+      # Make sure the input file exists
+      unless File.exist?(input_file)
+        warn("Input file #{input_file} does not exist")
         exit(1)
       end
 
-      ##  Maybe they didn't provide an output file name, so we'll guess
+      # Maybe they didn't provide an output file name, so we'll guess
       if @options[:output_file].nil?
         ext = File.extname(input_file)
-        @options[:output_file] = input_file.gsub(ext, '') + '.nes'
+        @options[:output_file] = "#{input_file.gsub(ext, '')}.nes"
       end
 
       if @options.values.any?(&:nil?)
-        STDERR.puts "Missing options try --help"
+        warn('Missing options try --help')
         exit(1)
       end
 
       N65::Assembler.from_file(input_file, @options)
     end
 
-
     private
 
-    ####
-    ##  Create a commandline option parser
     def create_option_parser
       OptionParser.new do |opts|
-        opts.banner = "Usage: #{$0} [options] <input_file.asm>"
+        opts.banner = "Usage: #{$PROGRAM_NAME} [options] <input_file.asm>"
 
         opts.on('-o', '--outfile filename', 'outfile') do |output_file|
-          @options[:output_file] = output_file;
+          @options[:output_file] = output_file
         end
 
         opts.on('-s', '--symbols', 'Outputs a symbol map') do
@@ -91,11 +81,7 @@ module N65
           puts opts
           exit
         end
-
-
       end
     end
-
   end
-
 end