注意：这个答案是正确的但现在已经过时了。看下面的正确答案。 TL; DR：现在使用'debugger'。

ruby​​-debug现在可用于Ruby 1.9.x.请参阅 http://www.github.com/mark-moseley

要安装（在1.9安装Ruby上使用gem）：

  gem install ruby​​-debug19 
 

（可能在前面需要sudo）。

What do you guys use for debugging in ruby 1.9? rdebug doesn't seem to be compatible.. is there anything out there?

Note: this answer was correct but is now out of date. See the below correct answer. TL;DR: use 'debugger' now.

ruby-debug is now available with Ruby 1.9.x. See http://www.github.com/mark-moseley

To install (using gem on 1.9 Ruby installation):

gem install ruby-debug19

(with perhaps the necessary 'sudo' in front of it).