# File cli/ruby-debug/commands/list.rb, line 16
    def execute
      listsize = Command.settings[:listsize]
      if !@match || !(@match[1] || @match[2])
        b = @state.previous_line ? 
        @state.previous_line + listsize : @state.line - (listsize/2)
        e = b + listsize - 1
      elsif @match[1] == '-'
        b = if @state.previous_line
              if  @state.previous_line > 0
                @state.previous_line - listsize 
              else
                @state.previous_line
              end
            else 
              @state.line - (listsize/2)
            end
        e = b + listsize - 1
      elsif @match[1] == '='
        @state.previous_line = nil
        b = @state.line - (listsize/2)
        e = b + listsize -1
      else
        b, e = @match[2].split(/[-,]/)
        if e
          b = b.to_i
          e = e.to_i
        else
          b = b.to_i - (listsize/2)
          e = b + listsize - 1
        end
      end
      @state.previous_line = display_list(b, e, @state.file, @state.line)
    end