假设我有一个非常简单的 Ruby 程序：
require 'rubygems'
require 'ruby-debug'
x = 1
debugger
puts x
当执行命中“调试器”命令时，它会正确停止并给我“rdb”提示。
现在：我的目标是让程序打印 2 而不是 1。如何做到这一点？如果我输入“帮助”，那么 rdebug 会告诉我：
ruby-debug help v0.10.4
Type 'help <command-name>' for help on a specific command
Available commands:
backtrace delete enable help method putl set trace
break disable eval info next quit show undisplay
catch display exit irb p reload step up
condition down finish kill pp restart thread var
continue edit frame list ps save tmate where
'set' 命令看起来很有希望......但是：
(rdb:1) help set
Modifies parts of the ruby-debug environment. Boolean values take
on, off, 1 or 0.
You can see these environment settings with the "show" command.
--
List of set subcommands:
--
set annotate -- Set annotation level
set args -- Set argument list to give program being debugged when it is started
set autoeval -- Evaluate every unrecognized command
set autolist -- Execute 'list' command on every breakpoint
set autoirb -- Invoke IRB on every stop
set autoreload -- Reload source code when changed
set basename -- Report file basename only showing file names
set callstyle -- Set how you want call parameters displayed
set debuggertesting -- Used when testing the debugger
set forcestep -- Make sure 'next/step' commands always move to a new line
set fullpath -- Display full file names in frames
set history -- Generic command for setting command history parameters
set keep-frame-bindings -- Save frame binding on each call
set linetrace+ -- Set line execution tracing to show different lines
set linetrace -- Set line execution tracing
set listsize -- Set number of source lines to list by default
set trace -- Display stack trace when 'eval' raises exception
set width -- Number of characters the debugger thinks are in a line
没有骰子。该怎么办？
我查看了Official ruby-debug doc和RailsGuides Debugging Rails Applications doc，但没有看到答案。