From: Pierre Barbier de Reuille <Pierre.Barbier_de_Reuille@...>
Date: 2006-03-23T01:09:58+09:00
Subject: Re: Reading from standard error

Hi !

I don't know if this is the best way to do it, but here is how I'll do :

rd,wt = IO.pipe # Prepare the pipe to get the output
id = fork do
  # Here we are in the child process
  # First get the system id of the pipe
  $stderr.reopen(f)
   # Then launch your process here
   exec("prog", arg1, ...)
end

# Here you can read the error output from rd
# If you want to wait for the end of the other process first :

Process.waitpid(id)

Pierre

PS: I hope this works as I am not on a UNIX machine and fork does not 
work :/ However I tried the IO.reopen part and this works fine.

Thiago Arrais a �crit :
> Maybe this one has already been answered somewhere. If so, my
> searching skills really suck.
>
> How can I start a sub-process from Ruby and read its standard error
> and standard output stream separately? I have tried to do it with
> IO.popen, but it only reads the output stream. The Process  module
> doesn't help either.
>
> Cheers,
>
> Thiago Arrais
>
>