[jruby-user] Behavior of 'system'. Jruby 1.5.3

[Bob Whiteside]

Hi All,

When I run the command:

    jruby -e "system '/usr/bin/ruby -v'"

the version output I see is from JRuby, rather that the Ruby that I expected.  I suspect that this is related to some optimization used to avoid launching new JVM's, or to make "Ruby" code work with "JRuby."

My question is, "How do I turn this off?"  I actually, really, want to run /usr/bin/ruby, and I've expressed that as clearly as I know how in the code.  My current hack is to write a little shell script (without 'ruby' in its filename!) and route the call through that, but that is really awkward.  Can I make JRuby run the actual command I tell it to?

Cheers,
--Bob

[Wayne Meissner]

See if system '/usr/bin/env ruby -v' works. That might confound the
jruby heuristics, and run the real ruby. Or you could try '/bin/sh
-c' instead of /usr/bin/env.

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[Hirotsugu Asari]

I believe this is a known issue: see http://bugs.jruby.org/5110

[Bob Whiteside]

Oh, Thanks, Wayne!  That worked!

Thanks, also, to Hirotsugu, but that appears to be a different issue.  My "system" command ran fine, it just ran teh wrong program. 

Cheers,
--Bob

[Roger Pack]

Bob Whiteside wrote:
> Hi All,
>
> When I run the command:
>
> jruby -e "system '/usr/bin/ruby -v'"
>
> the version output I see is from JRuby, rather that the Ruby that I
> expected. I suspect that this is related to some optimization used to
> avoid
> launching new JVM's, or to make "Ruby" code work with "JRuby."

Perhaps related to:

http://www.ruby-forum.com/topic/204508

?

(+1 for wishing the default of inproc were false--it's quite surprising
when you run into these bugs...)
--
Posted via http://www.ruby-forum.com/.

[Bob Whiteside]

Oh, thanks, Roger.  That is, indeed related.  Further more, reading over there, I learned about

jruby.launch.inproc=true

I did not know about this setting.  I will now go play with it! 

And, yes.  This was an expensive-in-time learning experience.  I understand why it was done, but still...


Cheers,
--Bob