为什么80%的码农都做不了架构师？>>> 
转自：http://www.yiibai.com/ruby/ruby_debugger.html
一种语言多么容易使用，它通常包含了一些错误，如果它是多长了几行。为了帮助交易与错误，Ruby的标准分配包括一个调试.
为了启动Ruby调试器，加载调试库使用的命令行选项-r调试。调试器之前停止的可执行代码的第一行，并要求输入用户命令.
使用语法:
下面是使用Ruby调试器的使用语法:
$ ruby -r debug filename[, ...]Ruby调试器命令:
下面是调试程序时，您可以使用完整的命令列表。这是没有必要使用完整的关键字给命令的一部分，在给[...]选项.
| SN | Command with Description |
|---|---|
| 1 | b[reak] [< file| class>:]< line| method> Sets breakpoint to some position. Breakpoint is a place where you want to pause program execution for debugging purpose. |
| 2 | wat[ch] expression Sets watchpoints |
| 3 | cat[ch] (exception|off) Sets catchpoint to an exception. |
| 4 | b[reak] Displays breakpoints and watchpoints |
| 5 | del[ete] [n] Deletes breakpoints |
| 6 | disp[lay] expression Displays value of expression |
| 7 | undisp[lay] [ n] Removes display of n |
| 8 | c[ont] Continues execution |
| 9 | s[tep] [ n] Executes next n lines stepping into methods |
| 10 | n[ext] [ n] Executes next n lines stepping over methods |
| 11 | w[here] Displays stack frame |
| 12 | f[rame] Synonym for where |
| 13 | l[ist][<-| n- m>] Displays source lines from n to m |
| 14 | up [ n] Moves up n levels in the stack frame |
| 15 | down [ n] Moves down n levels in the stack frame |
| 16 | fin[ish] Finishes execution of the current method |
| 17 | tr[ace] [on|off] Toggles trace mode on and off |
| 18 | q[uit] Exits debugger |
| 19 | v[ar] g[lobal] Displays global variables |
| 20 | v[ar] l[ocal] Displays local variables |
| 21 | v[ar] i[instance] object Displays instance variables of object |
| 22 | v[ar] c[onst] object Displays constants of object |
| 23 | m[ethod] i[instance] object Displays instance methods of object |
| 24 | m[ethod] class| module Displays instance methods of the class or module |
| 25 | th[read] l[ist] Displays threads |
| 26 | th[read] c[ur[rent]] Displays current thread |
| 27 | th[read] n Stops specified thread |
| 28 | th[read] stop > Synonym for th[read] n |
| 29 | th[read] c[ur[rent]] n> Synonym for th[read] n |
| 30 | th[read] resume > Resumes thread n |
| 31 | p expression Evaluates the expression |
| 32 | h[elp] Displays help message |
| 33 | everything else Evaluates. |
例子:
考虑下列文件hello.rb需要调试:
#!/usr/bin/env ruby
class Hello
def initialize( hello )
@hello = hello
end
def hello
@hello
end
end
salute = Hello.new( "Hello, Mac! - by www.yiibai.com" )
puts salute.hello这里是一个交互式会话捕获。大胆写在给定的命令:
[root@ruby]# ruby -r debug hello.rb Debug.rb
Emacs support available.
hello.rb:3:class Hello
(rdb:1) v l salute => nil
(rdb:1) b 10 Set breakpoint 1 at hello.rb:10
(rdb:1) c Hello, Mac!
[root@ruby]#