diff --git a/lib/uplot/command.rb b/lib/uplot/command.rb
index 05d137f..64d1b14 100644
--- a/lib/uplot/command.rb
+++ b/lib/uplot/command.rb
@@ -1,13 +1,14 @@
 require 'optparse'
 require_relative 'preprocessing'
 require_relative 'command/params'
+require_relative 'command/parser'
 
 module Uplot
   Data = Struct.new(:headers, :series)
 
   class Command
-    attr_accessor :params, :command
-    attr_reader :main_parser, :sub_parsers, :raw_inputs, :data, :fmt
+    attr_accessor :params
+    attr_reader :raw_inputs, :data, :fmt, :parser
 
     def initialize
       @params = Params.new
@@ -22,224 +23,15 @@ module Uplot
 
       @raw_inputs = []
       @debug      = false
+
+      @parser = Parser.new
     end
 
-    def create_default_parser
-      OptionParser.new do |opt|
-        opt.program_name = 'uplot'
-        opt.version = Uplot::VERSION
-        opt.on('-O', '--output', TrueClass) do |v|
-          @output = v
-        end
-        opt.on('-d', '--delimiter VAL', 'use DELIM instead of TAB for field delimiter', String) do |v|
-          @delimiter = v
-        end
-        opt.on('-H', '--headers', 'specify that the input has header row', TrueClass) do |v|
-          @headers = v
-        end
-        opt.on('-T', '--transpose', TrueClass) do |v|
-          @transpose = v
-        end
-        opt.on('-t', '--title VAL', 'print string on the top of plot', String) do |v|
-          params.title = v
-        end
-        opt.on('-x', '--xlabel VAL', 'print string on the bottom of the plot', String) do |v|
-          params.xlabel = v
-        end
-        opt.on('-y', '--ylabel VAL', 'print string on the far left of the plot', String) do |v|
-          params.ylabel = v
-        end
-        opt.on('-w', '--width VAL', 'number of characters per row', Integer) do |v|
-          params.width = v
-        end
-        opt.on('-h', '--height VAL', 'number of rows', Numeric) do |v|
-          params.height = v
-        end
-        opt.on('-b', '--border VAL', 'specify the style of the bounding box', String) do |v|
-          params.border = v.to_sym
-        end
-        opt.on('-m', '--margin VAL', 'number of spaces to the left of the plot', Numeric) do |v|
-          params.margin = v
-        end
-        opt.on('-p', '--padding VAL', 'space of the left and right of the plot', Numeric) do |v|
-          params.padding = v
-        end
-        opt.on('-c', '--color VAL', 'color of the drawing', String) do |v|
-          params.color = v =~ /\A[0-9]+\z/ ? v.to_i : v.to_sym
-        end
-        opt.on('--[no-]labels', 'hide the labels', TrueClass) do |v|
-          params.labels = v
-        end
-        opt.on('--fmt VAL', 'xyy, xyxy', String) do |v|
-          @fmt = v
-        end
-        opt.on('--debug', TrueClass) do |v|
-          @debug = v
-        end
-        yield opt if block_given?
-      end
-    end
-
-    def create_sub_parsers
-      parsers = Hash.new do |h, k|
-        h[k] = create_default_parser do |parser|
-          parser.banner = <<~MSG
-            Usage: uplot #{k} [options]
-
-            Options:
-          MSG
-        end
-      end
-
-      parsers[:barplot] = \
-        parsers[:bar]
-        .on('--symbol VAL', String) do |v|
-          params.symbol = v
-        end
-        .on('--xscale VAL', String) do |v|
-          params.xscale = v
-        end
-        .on('--count', TrueClass) do |v|
-          @count = v
-        end
-
-      parsers[:count] = \
-        parsers[:c] # barplot -c
-        .on('--symbol VAL', String) do |v|
-          params.symbol = v
-        end
-
-      parsers[:histogram] = \
-        parsers[:hist]
-        .on('-n', '--nbins VAL', Numeric) do |v|
-          params.nbins = v
-        end
-        .on('--closed VAL', String) do |v|
-          params.closed = v
-        end
-        .on('--symbol VAL', String) do |v|
-          params.symbol = v
-        end
-
-      parsers[:lineplot] = \
-        parsers[:line]
-        .on('--canvas VAL', String) do |v|
-          params.canvas = v
-        end
-        .on('--xlim VAL', String) do |v|
-          params.xlim = get_lim(v)
-        end
-        .on('--ylim VAL', String) do |v|
-          params.ylim = get_lim(v)
-        end
-
-      parsers[:lineplots] = \
-        parsers[:lines]
-        .on('--canvas VAL', String) do |v|
-          params.canvas = v
-        end
-        .on('--xlim VAL', String) do |v|
-          params.xlim = get_lim(v)
-        end
-        .on('--ylim VAL', String) do |v|
-          params.ylim = get_lim(v)
-        end
-
-      parsers[:scatter] = \
-        parsers[:s]
-        .on('--canvas VAL', String) do |v|
-          params.canvas = v
-        end
-        .on('--xlim VAL', String) do |v|
-          params.xlim = get_lim(v)
-        end
-        .on('--ylim VAL', String) do |v|
-          params.ylim = get_lim(v)
-        end
-
-      parsers[:density] = \
-        parsers[:d]
-        .on('--grid', TrueClass) do |v|
-          params.grid = v
-        end
-        .on('--xlim VAL', String) do |v|
-          params.xlim = get_lim(v)
-        end
-        .on('--ylim VAL', String) do |v|
-          params.ylim = get_lim(v)
-        end
-
-      parsers[:boxplot] = \
-        parsers[:box]
-        .on('--xlim VAL', String) do |v|
-          params.xlim = get_lim(v)
-        end
-
-      parsers[:colors]
-        .on('-n', '--names', TrueClass) do |v|
-          @color_names = v
-        end
-
-      # Preventing the generation of new sub-commands
-      parsers.default = nil
-      parsers
-    end
-
-    def create_main_parser
-      create_default_parser do |main_parser|
-        # Usage and help messages
-        main_parser.banner = \
-          <<~MSG
-            Program: uplot (Tools for plotting on the terminal)
-            Version: #{Uplot::VERSION} (using unicode_plot #{UnicodePlot::VERSION})
-
-            Usage:   uplot <command> [options]
-
-            Command:
-                #{sub_parsers.keys.join("\n    ")}
-
-            Options:
-          MSG
-      end
-    end
-
-    def parse_options(argv = ARGV)
-      @sub_parsers = create_sub_parsers
-      @main_parser = create_main_parser
-
-      begin
-        main_parser.order!(argv)
-      rescue OptionParser::ParseError => e
-        warn "uplot: #{e.message}"
-        exit 1
-      end
-
-      @command = argv.shift&.to_sym
-
-      unless sub_parsers.has_key?(command)
-        if command.nil?
-          warn main_parser.help
-        else
-          warn "uplot: unrecognized command '#{command}'"
-        end
-        exit 1
-      end
-      parser = sub_parsers[command]
-
-      begin
-        parser.parse!(argv) unless argv.empty?
-      rescue OptionParser::ParseError => e
-        warn "uplot: #{e.message}"
-        exit 1
-      end
-    end
-
-    def get_lim(str)
-      str.split(/-|:|\.\./)[0..1].map(&:to_f)
-    end
 
     def run
-      parse_options
+      parser.parse_options
+      command = parser.command
+      params = parser.params
 
       if command == :colors
         Plot.colors
diff --git a/lib/uplot/command/parser.rb b/lib/uplot/command/parser.rb
new file mode 100644
index 0000000..6b506fa
--- /dev/null
+++ b/lib/uplot/command/parser.rb
@@ -0,0 +1,225 @@
+module Uplot
+  class Command
+    class Parser
+      attr_reader :command, :params, :main_parser, :sub_parsers
+
+      def initialize
+        @sub_parsers = create_sub_parsers
+        @main_parser = create_main_parser
+        @command = nil
+        @params = Params.new
+      end
+
+      def create_default_parser
+        OptionParser.new do |opt|
+          opt.program_name = 'uplot'
+          opt.version = Uplot::VERSION
+          opt.on('-O', '--output', TrueClass) do |v|
+            @output = v
+          end
+          opt.on('-d', '--delimiter VAL', 'use DELIM instead of TAB for field delimiter', String) do |v|
+            @delimiter = v
+          end
+          opt.on('-H', '--headers', 'specify that the input has header row', TrueClass) do |v|
+            @headers = v
+          end
+          opt.on('-T', '--transpose', TrueClass) do |v|
+            @transpose = v
+          end
+          opt.on('-t', '--title VAL', 'print string on the top of plot', String) do |v|
+            params.title = v
+          end
+          opt.on('-x', '--xlabel VAL', 'print string on the bottom of the plot', String) do |v|
+            params.xlabel = v
+          end
+          opt.on('-y', '--ylabel VAL', 'print string on the far left of the plot', String) do |v|
+            params.ylabel = v
+          end
+          opt.on('-w', '--width VAL', 'number of characters per row', Integer) do |v|
+            params.width = v
+          end
+          opt.on('-h', '--height VAL', 'number of rows', Numeric) do |v|
+            params.height = v
+          end
+          opt.on('-b', '--border VAL', 'specify the style of the bounding box', String) do |v|
+            params.border = v.to_sym
+          end
+          opt.on('-m', '--margin VAL', 'number of spaces to the left of the plot', Numeric) do |v|
+            params.margin = v
+          end
+          opt.on('-p', '--padding VAL', 'space of the left and right of the plot', Numeric) do |v|
+            params.padding = v
+          end
+          opt.on('-c', '--color VAL', 'color of the drawing', String) do |v|
+            params.color = v =~ /\A[0-9]+\z/ ? v.to_i : v.to_sym
+          end
+          opt.on('--[no-]labels', 'hide the labels', TrueClass) do |v|
+            params.labels = v
+          end
+          opt.on('--fmt VAL', 'xyy, xyxy', String) do |v|
+            @fmt = v
+          end
+          opt.on('--debug', TrueClass) do |v|
+            @debug = v
+          end
+          yield opt if block_given?
+        end
+      end
+
+      def create_sub_parsers
+        parsers = Hash.new do |h, k|
+          h[k] = create_default_parser do |parser|
+            parser.banner = <<~MSG
+              Usage: uplot #{k} [options]
+
+              Options:
+            MSG
+          end
+        end
+
+        parsers[:barplot] = \
+          parsers[:bar]
+          .on('--symbol VAL', String) do |v|
+            params.symbol = v
+          end
+          .on('--xscale VAL', String) do |v|
+            params.xscale = v
+          end
+          .on('--count', TrueClass) do |v|
+            @count = v
+          end
+
+        parsers[:count] = \
+          parsers[:c] # barplot -c
+          .on('--symbol VAL', String) do |v|
+            params.symbol = v
+          end
+
+        parsers[:histogram] = \
+          parsers[:hist]
+          .on('-n', '--nbins VAL', Numeric) do |v|
+            params.nbins = v
+          end
+          .on('--closed VAL', String) do |v|
+            params.closed = v
+          end
+          .on('--symbol VAL', String) do |v|
+            params.symbol = v
+          end
+
+        parsers[:lineplot] = \
+          parsers[:line]
+          .on('--canvas VAL', String) do |v|
+            params.canvas = v
+          end
+          .on('--xlim VAL', String) do |v|
+            params.xlim = get_lim(v)
+          end
+          .on('--ylim VAL', String) do |v|
+            params.ylim = get_lim(v)
+          end
+
+        parsers[:lineplots] = \
+          parsers[:lines]
+          .on('--canvas VAL', String) do |v|
+            params.canvas = v
+          end
+          .on('--xlim VAL', String) do |v|
+            params.xlim = get_lim(v)
+          end
+          .on('--ylim VAL', String) do |v|
+            params.ylim = get_lim(v)
+          end
+
+        parsers[:scatter] = \
+          parsers[:s]
+          .on('--canvas VAL', String) do |v|
+            params.canvas = v
+          end
+          .on('--xlim VAL', String) do |v|
+            params.xlim = get_lim(v)
+          end
+          .on('--ylim VAL', String) do |v|
+            params.ylim = get_lim(v)
+          end
+
+        parsers[:density] = \
+          parsers[:d]
+          .on('--grid', TrueClass) do |v|
+            params.grid = v
+          end
+          .on('--xlim VAL', String) do |v|
+            params.xlim = get_lim(v)
+          end
+          .on('--ylim VAL', String) do |v|
+            params.ylim = get_lim(v)
+          end
+
+        parsers[:boxplot] = \
+          parsers[:box]
+          .on('--xlim VAL', String) do |v|
+            params.xlim = get_lim(v)
+          end
+
+        parsers[:colors]
+          .on('-n', '--names', TrueClass) do |v|
+            @color_names = v
+          end
+
+        # Preventing the generation of new sub-commands
+        parsers.default = nil
+        parsers
+      end
+
+      def create_main_parser
+        create_default_parser do |main_parser|
+          # Usage and help messages
+          main_parser.banner = \
+            <<~MSG
+              Program: uplot (Tools for plotting on the terminal)
+              Version: #{Uplot::VERSION} (using unicode_plot #{UnicodePlot::VERSION})
+
+              Usage:   uplot <command> [options]
+
+              Command:
+                  #{sub_parsers.keys.join("\n    ")}
+
+              Options:
+            MSG
+        end
+      end
+
+      def parse_options(argv = ARGV)
+        begin
+          main_parser.order!(argv)
+        rescue OptionParser::ParseError => e
+          warn "uplot: #{e.message}"
+          exit 1
+        end
+
+        @command = argv.shift&.to_sym
+
+        unless sub_parsers.has_key?(command)
+          if command.nil?
+            warn main_parser.help
+          else
+            warn "uplot: unrecognized command '#{command}'"
+          end
+          exit 1
+        end
+        parser = sub_parsers[command]
+
+        begin
+          parser.parse!(argv) unless argv.empty?
+        rescue OptionParser::ParseError => e
+          warn "uplot: #{e.message}"
+          exit 1
+        end
+      end
+
+      def get_lim(str)
+        str.split(/-|:|\.\./)[0..1].map(&:to_f)
+      end
+    end
+  end
+end