Ruby - ruby-debug terminating without error on 'if __FILE__ == $0'

I'm trying to use ruby-debug to debug this script I've written and it keeps terminating on the line, if __FILE__ == $0. I step through each line before it, and then when it gets to that line it just q开发者_JS百科uits. No errors or anything, it just quits. How do I fix this?

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Actually everything is working as it is supposed to. The if __FILE__ == $0 idiom basically translates to "if this file is the running program", which it is not if run from the debugger. See e.g. the following thread on ruby-talk for a discussion of this issue:

http://www.ruby-forum.com/topic/113859#new