diff --git a/lib/youplot/command.rb b/lib/youplot/command.rb
index c59eeae..9e55bf2 100644
--- a/lib/youplot/command.rb
+++ b/lib/youplot/command.rb
@@ -10,27 +10,23 @@ module YouPlot
   Data = Struct.new(:headers, :series)
 
   class Command
-    attr_accessor :params
-    attr_reader :data, :fmt, :parser
+    attr_accessor :command, :params, :options
+    attr_reader :data, :parser
 
     def initialize(argv = ARGV)
       @argv    = argv
       @parser  = Parser.new
+      @command = nil
+      @params  = nil
+      @options = nil
       @backend = YouPlot::Backends::UnicodePlotBackend
     end
 
     def run
       parser.parse_options(@argv)
-      command   = parser.command
-      @params   = parser.params
-      delimiter = parser.delimiter
-      transpose = parser.transpose
-      headers   = parser.headers
-      pass      = parser.pass
-      output    = parser.output
-      fmt       = parser.fmt
-      @encoding = parser.encoding
-      @debug    = parser.debug
+      @command ||= parser.command
+      @options ||= parser.options
+      @params  ||= parser.params
 
       if command == :colors
         @backend.colors(parser.color_names)
@@ -41,52 +37,52 @@ module YouPlot
       while (input = Kernel.gets(nil))
 
         # Pass the input to subsequent pipelines
-        case pass
+        case @options[:pass]
         when IO
-          pass.print(input)
+          @options[:pass].print(input)
         else
-          if pass
-            File.open(pass, 'w') do |f|
+          if @options[:pass]
+            File.open(@options[:pass], 'w') do |f|
               f.print(input)
             end
           end
         end
 
-        @data = if @encoding
-                  input2 = input.dup.force_encoding(@encoding).encode('utf-8')
-                  DSVReader.input(input2, delimiter, headers, transpose)
+        @data = if @options[:encoding]
+                  input2 = input.dup.force_encoding(@options[:encoding]).encode('utf-8')
+                  DSVReader.input(input2, @options[:delimiter], @options[:headers], @options[:transpose])
                 else
-                  DSVReader.input(input, delimiter, headers, transpose)
+                  DSVReader.input(input, @options[:delimiter], @options[:headers], @options[:transpose])
                 end
 
-        pp @data if @debug
+        pp @data if @options[:debug]
 
         plot = case command
                when :bar, :barplot
-                 @backend.barplot(data, params, fmt)
+                 @backend.barplot(data, params, @options[:fmt])
                when :count, :c
                  @backend.barplot(data, params, count: true)
                when :hist, :histogram
                  @backend.histogram(data, params)
                when :line, :lineplot
-                 @backend.line(data, params, fmt)
+                 @backend.line(data, params, @options[:fmt])
                when :lines, :lineplots
-                 @backend.lines(data, params, fmt)
+                 @backend.lines(data, params, @options[:fmt])
                when :scatter, :s
-                 @backend.scatter(data, params, fmt)
+                 @backend.scatter(data, params, @options[:fmt])
                when :density, :d
-                 @backend.density(data, params, fmt)
+                 @backend.density(data, params, @options[:fmt])
                when :box, :boxplot
                  @backend.boxplot(data, params)
                else
                  raise "unrecognized plot_type: #{command}"
                end
 
-        case output
+        case @options[:output]
         when IO
-          plot.render(output)
+          plot.render(@options[:output])
         else
-          File.open(output, 'w') do |f|
+          File.open(@options[:output], 'w') do |f|
             plot.render(f)
           end
         end
diff --git a/lib/youplot/command/cmd_options.rb b/lib/youplot/command/cmd_options.rb
new file mode 100644
index 0000000..ff4dbbe
--- /dev/null
+++ b/lib/youplot/command/cmd_options.rb
@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+module YouPlot
+  class Command
+    CmdOptions = Struct.new(
+      :delimiter,
+      :transpose,
+      :headers,
+      :pass,
+      :output,
+      :fmt,
+      :encoding,
+      :color_names,
+      :debug,
+      keyword_init: true
+    )
+  end
+end
diff --git a/lib/youplot/command/parser.rb b/lib/youplot/command/parser.rb
index 866fe05..fea5bb6 100644
--- a/lib/youplot/command/parser.rb
+++ b/lib/youplot/command/parser.rb
@@ -1,29 +1,30 @@
 # frozen_string_literal: true
 
 require 'optparse'
+require_relative 'cmd_options'
 require_relative 'plot_params'
 
 module YouPlot
   class Command
     class Parser
-      attr_reader :command, :params,
-                  :delimiter, :transpose, :headers, :pass, :output, :fmt,
-                  :color_names, :encoding, :debug
+      attr_reader :command, :options, :params
 
       def initialize
-        @command     = nil
-        @params      = PlotParams.new
+        @command = nil
 
-        @delimiter   = "\t"
-        @transpose   = false
-        @headers     = nil
-        @pass        = false
-        @output      = $stderr
-        @fmt         = 'xyy'
-        @encoding    = nil
-        @color_names = false
+        @options = CmdOptions.new(
+          delimiter: "\t",
+          transpose: false,
+          headers: nil,
+          pass: false,
+          output: $stderr,
+          fmt: 'xyy',
+          encoding: nil,
+          color_names: false,
+          debug: false
+        )
         
-        @debug       = false
+        @params = PlotParams.new
       end
 
       def create_default_parser
@@ -36,19 +37,19 @@ module YouPlot
           opt.on('Common options:')
           opt.on('-O', '--pass [VAL]', 'file to output standard input data to [stdout]',
                  'for inserting YouPlot in the middle of Unix pipes') do |v|
-            @pass = v || $stdout
+            @options[:pass] = v || $stdout
           end
           opt.on('-o', '--output VAL', 'file to output results to [stderr]') do |v|
-            @output = v
+            @options[:output] = v
           end
           opt.on('-d', '--delimiter VAL', String, 'use DELIM instead of TAB for field delimiter') do |v|
-            @delimiter = v
+            @options[:delimiter] = v
           end
           opt.on('-H', '--headers', TrueClass, 'specify that the input has header row') do |v|
-            @headers = v
+            @options[:headers] = v
           end
           opt.on('-T', '--transpose', TrueClass, 'transpose the axes of the input data') do |v|
-            @transpose = v
+            @options[:transpose] = v
           end
           opt.on('-t', '--title VAL', String, 'print string on the top of plot') do |v|
             params.title = v
@@ -81,10 +82,10 @@ module YouPlot
             params.labels = v
           end
           opt.on('--progress', TrueClass, 'progressive') do |v|
-            @progressive = v
+            @options[:progressive] = v
           end
           opt.on('--encoding VAL', String, 'Specify the input encoding') do |v|
-            @encoding = v
+            @options[:encoding] = v
           end
           # Optparse adds the help option, but it doesn't show up in usage.
           # This is why you need the code below.
@@ -93,7 +94,7 @@ module YouPlot
             exit
           end
           opt.on('--debug', TrueClass, 'print preprocessed data') do |v|
-            @debug = v
+            @options[:debug] = v
           end
           yield opt if block_given?
         end
@@ -167,7 +168,7 @@ module YouPlot
               params.xscale = v
             end
             parser.on_head('--fmt VAL', String, 'xy : header is like x, y...', 'yx : header is like y, x...') do |v|
-              @fmt = v
+              @options[:fmt] = v
             end
 
           when :count, :c
@@ -197,7 +198,7 @@ module YouPlot
               params.ylim = v.take(2)
             end
             parser.on_head('--fmt VAL', String, 'xy : header is like x, y...', 'yx : header is like y, x...') do |v|
-              @fmt = v
+              @options[:fmt] = v
             end
 
           when :lineplots, :lines
@@ -211,7 +212,7 @@ module YouPlot
               params.ylim = v.take(2)
             end
             parser.on_head('--fmt VAL', String, 'xyxy : header is like x1, y1, x2, y2, x3, y3...', 'xyy  : header is like x, y1, y2, y2, y3...') do |v|
-              @fmt = v
+              @options[:fmt] = v
             end
 
           when :scatter, :s
@@ -225,7 +226,7 @@ module YouPlot
               params.ylim = v.take(2)
             end
             parser.on_head('--fmt VAL', String, 'xyxy : header is like x1, y1, x2, y2, x3, y3...', 'xyy  : header is like x, y1, y2, y2, y3...') do |v|
-              @fmt = v
+              @options[:fmt] = v
             end
 
           when :density, :d
@@ -239,7 +240,7 @@ module YouPlot
               params.ylim = v.take(2)
             end
             parser.on('--fmt VAL', String, 'xyxy : header is like x1, y1, x2, y2, x3, y3...', 'xyy  : header is like x, y1, y2, y2, y3...') do |v|
-              @fmt = v
+              @options[:fmt] = v
             end
 
           when :boxplot, :box
@@ -249,7 +250,7 @@ module YouPlot
 
           when :colors
             parser.on_head('-n', '--names', 'show color names only', TrueClass) do |v|
-              @color_names = v
+              @options[:color_names] = v
             end
 
           else