On Jul 24, 2008, at 19:35 , Tanaka Akira wrote:

> In article  
> <3454c9680807241200xf7cc766qb987905a3987bb78 / mail.gmail.com>,
>  "Vladimir Sizikov" <vsizikov / gmail.com> writes:
>
>> Now that Rubinius and JRuby define RUBY_ENGINE, and RubyGems also  
>> uses
>> RUBY_ENGINE, maybe it's a good time to revisit the issue?
>
> What the usage of RUBY_ENGINE?
>
> I heard it is used to know command name at the IRC meeting.
> I think it is not good idea.

not command name, but ruby "flavor": (mri) ruby, rubinius, jruby, etc.