diff --git a/lib/pry/code.rb b/lib/pry/code.rb
index 53d88e13..14200f78 100644
--- a/lib/pry/code.rb
+++ b/lib/pry/code.rb
@@ -1,4 +1,17 @@
 class Pry
+  class << self
+    def Code(obj)
+      case obj
+      when Code
+        obj
+      when ::Method, Pry::Method, UnboundMethod, Proc
+        Code.from_method(obj)
+      else
+        Code.new(obj)
+      end
+    end
+  end
+
   class Code
     class << self
       # Instantiate a `Code` object containing code loaded from a file or
@@ -13,7 +26,7 @@ class Pry
           if File.readable?(fn)
             f = File.open(fn, 'r')
           else
-            raise CommandError, "Cannot open #{file.inspect} for reading."
+            raise CommandError, "Cannot open #{fn.inspect} for reading."
           end
         end
         new(f, 1, code_type)
@@ -34,6 +47,8 @@ class Pry
       end
     end
 
+    attr_accessor :code_type
+
     # @param [Array<String>] lines
     # @param [Fixnum?] (1) start_line
     # @param [Symbol?] (:ruby) code_type
@@ -57,6 +72,8 @@ class Pry
     alias << push
 
     def before(line_num, lines=1)
+      return self unless line_num
+
       dup.instance_eval do
         @lines = @lines.select { |l, ln| ln >= line_num - lines && ln < line_num }
         self
@@ -64,13 +81,19 @@ class Pry
     end
 
     def between(start_line, end_line)
+      return self unless start_line && end_line
+      start_line -= 1 unless start_line < 0
+      end_line   -= 1 unless end_line   < 0
+
       dup.instance_eval do
-        @lines = @lines[(start_line + 1)..(end_line + 1)]
+        @lines = @lines[start_line..end_line] || []
         self
       end
     end
 
     def around(line_num, lines=1)
+      return self unless line_num
+
       dup.instance_eval do
         @lines = @lines.select { |l, ln| ln >= line_num - lines && ln <= line_num + lines }
         self
@@ -78,6 +101,8 @@ class Pry
     end
 
     def after(line_num, lines=1)
+      return self unless line_num
+
       dup.instance_eval do
         @lines = @lines.select { |l, ln| ln > line_num && ln <= line_num + lines }
         self
@@ -101,6 +126,14 @@ class Pry
       end
     end
 
+    def with_indentation(spaces=0)
+      dup.instance_eval do
+        @with_indentation = !!spaces
+        @indentation_num  = spaces
+        self
+      end
+    end
+
     # @return [String]
     def inspect
       Object.instance_method(:to_s).bind(self).call
@@ -134,7 +167,13 @@ class Pry
         end
       end
 
-      lines.map(&:first).join("\n")
+      if @with_indentation
+        lines.each do |l|
+          l[0] = "#{' ' * @indentation_num}#{l[0]}"
+        end
+      end
+
+      lines.map { |l| "#{l.first}\n" }.join
     end
 
     def method_missing(name, *args, &blk)
diff --git a/lib/pry/default_commands/shell.rb b/lib/pry/default_commands/shell.rb
index ad3deac4..6a14af2f 100644
--- a/lib/pry/default_commands/shell.rb
+++ b/lib/pry/default_commands/shell.rb
@@ -28,67 +28,93 @@ class Pry
           _pry_.instance_eval(&Pry::FILE_COMPLETIONS)
         end
       end
-
       alias_command "file-mode", "shell-mode"
 
-      command "cat", "Show code from a file or Pry's input buffer. Type `cat --help` for more information." do |*args|
-        start_line = 0
-        end_line = -1
-        file_name = nil
-        bt_index = 0
+      command_class "cat", "Show code from a file or Pry's input buffer. Type `cat --help` for more information." do
+        banner <<-USAGE
+          Usage: cat FILE
+                 cat --ex [STACK_INDEX]
+                 cat --in [INPUT_INDEX_OR_RANGE]
 
-        opts = Slop.parse!(args) do |opt|
-          opt.on :s, :start, "Start line (defaults to start of file)Line 1 is the first line.", true, :as => Integer do |line|
-            start_line = line - 1
-          end
+          cat is capable of showing part or all of a source file, the context of the
+          last exception, or an expression from Pry's input history.
 
-          opt.on :e, :end, "End line (defaults to end of file). Line -1 is the last line", true, :as => Integer do |line|
-            end_line = line - 1
-          end
+          cat --ex defaults to showing the lines surrounding the location of the last
+          exception. Invoking it more than once travels up the exception's backtrace,
+          and providing a number shows the context of the given index of the backtrace.
+        USAGE
 
-          opt.on :ex, "Show a window of N lines either side of the last exception (defaults to 5).", :optional => true, :as => Integer do |bt_index_arg|
-            window_size = Pry.config.exception_window_size || 5
-            ex = _pry_.last_exception
-            next if !ex
-            if bt_index_arg
-              bt_index = bt_index_arg
-            else
-              bt_index = ex.bt_index
-            end
-            ex.bt_index = (bt_index + 1) % ex.backtrace.size
+        def options(opt)
+          opt.on :ex,        "Show the context of the last exception.", :optional => true, :as => Integer
+          opt.on :i, :in,    "Show one or more entries from Pry's expression history.", :optional => true, :as => Range, :default => -5..-1
 
-            ex_file, ex_line = ex.bt_source_location_for(bt_index)
-            start_line = (ex_line - 1) - window_size
-            start_line = start_line < 0 ? 0 : start_line
-            end_line = (ex_line - 1) + window_size
-            if ex_file && RbxPath.is_core_path?(ex_file)
-              file_name = RbxPath.convert_path_to_full(ex_file)
-            else
-              file_name = ex_file
-            end
-          end
+          opt.on :s, :start, "Starting line (defaults to the first line).", :optional => true, :as => Integer
+          opt.on :e, :end,   "Ending line (defaults to the last line).", :optional => true, :as => Integer
+          opt.on :l, :'line-numbers', "Show line numbers."
+          opt.on :t, :type,  "The file type for syntax highlighting (e.g., 'ruby' or 'python').", true, :as => Symbol
 
-          opt.on :i, :in, "Show entries from Pry's input expression history. Takes an index or range.", :optional => true, :as => Range, :default => -5..-1
-
-          opt.on :l, "line-numbers", "Show line numbers."
-          opt.on :t, :type, "The specific file type for syntax higlighting (e.g ruby, python)", true, :as => Symbol
           opt.on :f, :flood, "Do not use a pager to view text longer than one screen."
-          opt.on :h, :help, "This message." do
-            output.puts opt.help
+        end
+
+        def process
+          handler = case
+            when opts.present?(:ex)
+              method :process_ex
+            when opts.present?(:in)
+              method :process_in
+            else
+              method :process_file
+            end
+
+          handler.call do |code|
+            code.code_type = opts[:type] || :ruby
+
+            code.
+              between(opts[:start] || 1, opts[:end] || -1).
+              with_line_numbers(opts.present?(:'line-numbers') || opts.present?(:ex))
           end
         end
 
-        next if opts.present?(:help)
+        def process_ex
+          window_size = Pry.config.exception_window_size || 5
+          ex = _pry_.last_exception
 
-        if opts.present?(:ex)
-          if file_name.nil?
-            raise CommandError, "No Exception or Exception has no associated file."
+          raise CommandError, "No exception found." unless ex
+
+          if opts[:ex].nil?
+            bt_index = ex.bt_index
+            ex.inc_bt_index
+          else
+            bt_index = opts[:ex]
           end
-        else
-          file_name = args.shift
+
+          ex_file, ex_line = ex.bt_source_location_for(bt_index)
+
+          raise CommandError, "The given backtrace level is out of bounds." unless ex_file
+
+          if RbxPath.is_core_path?(ex_file)
+            ex_file = RbxPath.convert_path_to_full(ex_file)
+          end
+
+          start_line = ex_line - window_size
+          start_line = 1 if start_line < 1
+          end_line = ex_line + window_size
+
+          header = unindent <<-HEADER
+            #{text.bold 'Exception:'} #{ex.class}: #{ex.message}
+            --
+            #{text.bold('From:')} #{ex_file} @ line #{ex_line} @ #{text.bold("level: #{bt_index}")} of backtrace (of #{ex.backtrace.size - 1}).
+
+          HEADER
+
+          code = yield(Pry::Code.from_file(ex_file).
+                         between(start_line, end_line).
+                         with_marker(ex_line))
+
+          render_output("#{header}#{code}", opts)
         end
 
-        if opts.present?(:in)
+        def process_in
           normalized_range = absolute_index_range(opts[:i], _pry_.input_array.length)
           input_items = _pry_.input_array[normalized_range] || []
 
@@ -98,66 +124,30 @@ class Pry
             raise CommandError, "No expressions found."
           end
 
-          if opts[:i].is_a?(Range)
+          if zipped_items.length > 1
             contents = ""
-
             zipped_items.each do |i, s|
               contents << "#{text.bold(i.to_s)}:\n"
-
-              code = syntax_highlight_by_file_type_or_specified(s, nil, :ruby)
-
-              if opts.present?(:'line-numbers')
-                contents << text.indent(text.with_line_numbers(code, 1), 2)
-              else
-                contents << text.indent(code, 2)
-              end
+              contents << yield(Pry::Code(s).with_indentation(2)).to_s
             end
           else
-            contents = syntax_highlight_by_file_type_or_specified(zipped_items.first.last, nil, :ruby)
+            contents = yield(Pry::Code(zipped_items.first.last))
           end
-        else
+
+          render_output(contents, opts)
+        end
+
+        def process_file
+          file_name = args.shift
+
           unless file_name
-            raise CommandError, "Must provide a file name."
+            raise CommandError, "Must provide a filename, --in, or --ex."
           end
 
-          begin
-            contents, _, _ = read_between_the_lines(file_name, start_line, end_line)
-          rescue Errno::ENOENT
-            raise CommandError, "Could not find file: #{file_name}"
-          end
+          code = yield(Pry::Code.from_file(file_name))
 
-          contents = syntax_highlight_by_file_type_or_specified(contents, file_name, opts[:type])
-
-          if opts.present?(:'line-numbers')
-            contents = text.with_line_numbers contents, start_line + 1
-          end
-        end
-
-        # add the arrow pointing to line that caused the exception
-        if opts.present?(:ex)
-          ex_file, ex_line = _pry_.last_exception.bt_source_location_for(bt_index)
-          contents = text.with_line_numbers contents, start_line + 1, :bright_red
-
-          contents = contents.lines.each_with_index.map do |line, idx|
-            l = idx + start_line
-            if l == (ex_line - 1)
-              " =>#{line}"
-            else
-              "   #{line}"
-            end
-          end.join
-
-          # header for exceptions
-          output.puts "\n#{Pry::Helpers::Text.bold('Exception:')} #{_pry_.last_exception.class}: #{_pry_.last_exception.message}\n--"
-          output.puts "#{Pry::Helpers::Text.bold('From:')} #{ex_file} @ line #{ex_line} @ #{text.bold('level: ')} #{bt_index} of backtrace (of #{_pry_.last_exception.backtrace.size - 1}).\n\n"
-        end
-
-        set_file_and_dir_locals(file_name)
-
-        if opts.present?(:flood)
-          output.puts contents
-        else
-          stagger_output(contents)
+          set_file_and_dir_locals(file_name)
+          render_output(code, opts)
         end
       end
     end
diff --git a/lib/pry/helpers/command_helpers.rb b/lib/pry/helpers/command_helpers.rb
index 236b5ef6..694c6b5f 100644
--- a/lib/pry/helpers/command_helpers.rb
+++ b/lib/pry/helpers/command_helpers.rb
@@ -15,6 +15,14 @@ class Pry
         file.close(opts[:unlink])
       end
 
+      def render_output(str, opts={})
+        if opts[:flood]
+          output.puts str
+        else
+          stagger_output str
+        end
+      end
+
       def get_method_or_raise(name, target, opts={}, omit_help=false)
         meth = Pry::Method.from_str(name, target, opts)
 
diff --git a/lib/pry/pry_instance.rb b/lib/pry/pry_instance.rb
index bd1b1cd3..67f0f347 100644
--- a/lib/pry/pry_instance.rb
+++ b/lib/pry/pry_instance.rb
@@ -15,10 +15,11 @@ class Pry
   attr_accessor :binding_stack
 
   attr_accessor :last_result
-  attr_accessor :last_exception
   attr_accessor :last_file
   attr_accessor :last_dir
 
+  attr_reader :last_exception
+
   attr_reader :input_array
   attr_reader :output_array
 
@@ -228,7 +229,8 @@ class Pry
     result = set_last_result(target.eval(code, Pry.eval_path, Pry.current_line), target)
     result
   rescue RescuableException => e
-    result = set_last_exception(e, target)
+    self.last_exception = e
+    e
   ensure
     update_input_history(code)
     hooks.exec_hook :after_eval, result, self
@@ -406,16 +408,18 @@ class Pry
   end
 
   # Set the last exception for a session.
-  # This method should not need to be invoked directly.
-  # @param [Exception] ex The exception.
-  # @param [Binding] target The binding to set `_ex_` on.
-  def set_last_exception(ex, target)
+  # @param [Exception] ex
+  def last_exception=(ex)
     class << ex
       attr_accessor :file, :line, :bt_index
       def bt_source_location_for(index)
         backtrace[index] =~ /(.*):(\d+)/
         [$1, $2.to_i]
       end
+
+      def inc_bt_index
+        @bt_index = (@bt_index + 1) % backtrace.size
+      end
     end
 
     ex.bt_index = 0
@@ -423,8 +427,7 @@ class Pry
 
     @last_result_is_exception = true
     @output_array << ex
-
-    self.last_exception = ex
+    @last_exception = ex
   end
 
   # Update Pry's internal state after evalling code.
diff --git a/test/helper.rb b/test/helper.rb
index b30d216c..4f1d8cd0 100644
--- a/test/helper.rb
+++ b/test/helper.rb
@@ -30,23 +30,12 @@ class << Pry
   end
 end
 
-class MockPryException
-  attr_accessor :bt_index
-  attr_accessor :backtrace
-
-  def initialize(*backtrace)
-    @backtrace = backtrace
-    @bt_index = 0
-  end
-
-  def message
-    "mock exception"
-  end
-
-  def bt_source_location_for(index)
-    backtrace[index] =~ /(.*):(\d+)/
-    [$1, $2.to_i]
+def mock_exception(*mock_backtrace)
+  e = StandardError.new("mock exception")
+  (class << e; self; end).class_eval do
+    define_method(:backtrace) { mock_backtrace }
   end
+  e
 end
 
 Pry.reset_defaults
diff --git a/test/test_default_commands/test_introspection.rb b/test/test_default_commands/test_introspection.rb
index 6fdb558c..4bd00a41 100644
--- a/test/test_default_commands/test_introspection.rb
+++ b/test/test_default_commands/test_introspection.rb
@@ -133,7 +133,7 @@ describe "Pry::DefaultCommands::Introspection" do
 
       it 'should start editor on first level of backtrace when --ex used with no argument ' do
         pry_instance = Pry.new(:input => StringIO.new("edit -n --ex"), :output => StringIO.new)
-        pry_instance.last_exception = MockPryException.new("a:1", "b:2", "c:3")
+        pry_instance.last_exception = mock_exception("a:1", "b:2", "c:3")
         pry_instance.rep(self)
         @__ex_file__.should == "a"
         @__ex_line__.should == 1
@@ -141,7 +141,7 @@ describe "Pry::DefaultCommands::Introspection" do
 
       it 'should start editor on first level of backtrace when --ex 0 used ' do
         pry_instance = Pry.new(:input => StringIO.new("edit -n --ex 0"), :output => StringIO.new)
-        pry_instance.last_exception = MockPryException.new("a:1", "b:2", "c:3")
+        pry_instance.last_exception = mock_exception("a:1", "b:2", "c:3")
         pry_instance.rep(self)
         @__ex_file__.should == "a"
         @__ex_line__.should == 1
@@ -149,7 +149,7 @@ describe "Pry::DefaultCommands::Introspection" do
 
       it 'should start editor on second level of backtrace when --ex 1 used' do
         pry_instance = Pry.new(:input => StringIO.new("edit -n --ex 1"), :output => StringIO.new)
-        pry_instance.last_exception = MockPryException.new("a:1", "b:2", "c:3")
+        pry_instance.last_exception = mock_exception("a:1", "b:2", "c:3")
         pry_instance.rep(self)
         @__ex_file__.should == "b"
         @__ex_line__.should == 2
@@ -157,7 +157,7 @@ describe "Pry::DefaultCommands::Introspection" do
 
       it 'should start editor on third level of backtrace when --ex 2 used' do
         pry_instance = Pry.new(:input => StringIO.new("edit -n --ex 2"), :output => StringIO.new)
-        pry_instance.last_exception = MockPryException.new("a:1", "b:2", "c:3")
+        pry_instance.last_exception = mock_exception("a:1", "b:2", "c:3")
         pry_instance.rep(self)
         @__ex_file__.should == "c"
         @__ex_line__.should == 3
@@ -165,7 +165,7 @@ describe "Pry::DefaultCommands::Introspection" do
 
       it 'should display error message when backtrace level is out of bounds (using --ex 4)' do
         pry_instance = Pry.new(:input => StringIO.new("edit -n --ex 4"), :output => str_output = StringIO.new)
-        pry_instance.last_exception = MockPryException.new("a:1", "b:2", "c:3")
+        pry_instance.last_exception = mock_exception("a:1", "b:2", "c:3")
         pry_instance.rep(self)
         str_output.string.should =~ /Exception has no associated file/
       end
diff --git a/test/test_default_commands/test_shell.rb b/test/test_default_commands/test_shell.rb
index 9544d720..926586f7 100644
--- a/test/test_default_commands/test_shell.rb
+++ b/test/test_default_commands/test_shell.rb
@@ -5,7 +5,7 @@ describe "Pry::DefaultCommands::Shell" do
 
     describe "on receiving a file that does not exist" do
       it 'should display an error message' do
-        mock_pry("cat supercalifragilicious66").should =~ /Could not find file/
+        mock_pry("cat supercalifragilicious66").should =~ /Cannot open/
       end
     end
 
@@ -65,7 +65,7 @@ describe "Pry::DefaultCommands::Shell" do
         temp_file do |f|
           f << "bt number 1"
           f.flush
-          pry_instance.last_exception = MockPryException.new("#{f.path}:1", "x", "x")
+          pry_instance.last_exception = mock_exception("#{f.path}:1", "x", "x")
           pry_instance.rep(self)
         end
 
@@ -78,7 +78,7 @@ describe "Pry::DefaultCommands::Shell" do
         temp_file do |f|
           f << "bt number 1"
           f.flush
-          pry_instance.last_exception = MockPryException.new("#{f.path}:1", "x", "x")
+          pry_instance.last_exception = mock_exception("#{f.path}:1", "x", "x")
           pry_instance.rep(self)
         end
 
@@ -91,31 +91,31 @@ describe "Pry::DefaultCommands::Shell" do
         temp_file do |f|
           f << "bt number 2"
           f.flush
-          pry_instance.last_exception = MockPryException.new("x", "#{f.path}:1", "x")
+          pry_instance.last_exception = mock_exception("x", "#{f.path}:1", "x")
           pry_instance.rep(self)
         end
 
         str_output.string.should =~ /bt number 2/
       end
 
-      it 'should cat third level of backtrace when --ex 2 used ' do
+      it 'should cat third level of backtrace when --ex 2 used' do
         pry_instance = Pry.new(:input => StringIO.new("cat --ex 2"), :output => str_output = StringIO.new)
 
         temp_file do |f|
           f << "bt number 3"
           f.flush
-          pry_instance.last_exception = MockPryException.new("x", "x", "#{f.path}:1")
+          pry_instance.last_exception = mock_exception("x", "x", "#{f.path}:1")
           pry_instance.rep(self)
         end
 
         str_output.string.should =~ /bt number 3/
       end
 
-      it 'should show error when backtrace level out of bounds  ' do
+      it 'should show error when backtrace level out of bounds' do
         pry_instance = Pry.new(:input => StringIO.new("cat --ex 3"), :output => str_output = StringIO.new)
-        pry_instance.last_exception = MockPryException.new("x", "x", "x")
+        pry_instance.last_exception = mock_exception("x", "x", "x")
         pry_instance.rep(self)
-        str_output.string.should =~ /No Exception or Exception has no associated file/
+        str_output.string.should =~ /out of bounds/
       end
 
       it 'each successive cat --ex should show the next level of backtrace, and going past the final level should return to the first' do
@@ -129,7 +129,7 @@ describe "Pry::DefaultCommands::Shell" do
         pry_instance = Pry.new(:input => StringIO.new("cat --ex\n" * 4),
                                :output => (str_output = StringIO.new))
 
-        pry_instance.last_exception = MockPryException.new(*temp_files.map { |f| "#{f.path}:1" })
+        pry_instance.last_exception = mock_exception(*temp_files.map { |f| "#{f.path}:1" })
 
         3.times do |i|
           pry_instance.rep(self)