[Tutor] Pipe variable to external command (fwd)

[Jeffrey Rice]

At 11:56 AM 5/12/2005, Danny Yoo wrote:
>* * * *
>CLAMAV_out, CLAMAV_in, CLAMAV_err= popen2.popen3(CLAMAV)
>CLAMAV_in.write(WORKING)
>CLAMAV_in.close()
>CLAM_RESULT=CLAMAV_out.read()
>CLAMAV_out.close()
>CLAM_ERR=CLAMAV_err.read()
>CLAMAV_err.close()
>* * * *
>
>CLAM_RESULT gives the correct reply, and stderr is 1.  But CLAM_ERR is
>empty.  This seems like it should be simple -- what am I missing?

I think I am messing this up!  What I actually need is the exitcode of the 
spawned command, which is why stderr did not contain the info I wanted.  It 
seems there is a new problem: to get the exitcode of the spawned process, 
not the "shell" that contains it.  I found this example on another list 
that seems to address this problem:

http://www.ruby-talk.org/cgi-bin/scat.rb/ruby/ruby-talk/68786
As a work around, I end up calling popen3 like this:

Open3.popen3 ("/some/command/to/run ; echo $? 1>&2") { ... }

That ensures the exit code from /some/command/to/run will be the last
line of the standard error stream from Open3.popen3. Then I can just
pull that line off the output to get the return code.


Is there a more elegant way to get the exitcode off the child process, or 
is this the "approved" method?

Jeff

*       *       *       *       *       *       *
Jeffrey Rice    ||     jeffrice at finity.org      ||  www.finity.org