From: James Gray <james@...>
Date: 2009-04-20T11:43:00+09:00
Subject: Re: what's the differences between IO.popen ( or IO.pipe) and PTY.spawn??

On Apr 19, 2009, at 9:17 PM, Jun Young Kim wrote:

> The program I want to execute as a external program in ruby is using  
> a write system call.
>
> When I use IO.popen or IO.pipe, there is no output because of the  
> external program didn't flush it's output. (but, when I executed it  
> in shell, normally it shows up outputs).

Try doing it this way:

   output = IO.popen("command here", "w+") { |cmd|
     cmd.close_write
     cmd.read
   }

A lot of times, closing the writing stream will trigger the output.   
Hope that helps.

James Edward Gray II