From: Stefano Crocco <stefano.crocco@...>
Date: 2008-07-17T16:46:43+09:00
Subject: Re: continue the execution of a ruby script after a shell comand

On Thursday 17 July 2008, Hamlat Ameziane wrote:
> Hi,
> I have a little problem,I will be grateful if someone can help me.
>
> So I have this script :
>
> puts '*** Beginning of the script ***'
> path = 'C:\another_script.rb'
> exec 'ruby '+path
> puts '*** End of the script ***'
>
>
> And I have the following result :
>
> puts '*** Beginning of the script ***'
> ## execution of script C:\another_script.rb
>
>
> But Ruby dont print the last line : *** End of the script ***
>
> I have tried this :
>
> t = Thread.new {exec 'ruby '+path}
> Thread.pass (t)
>
> But I have the same result !!!!

From ri for Kernel#exec:

"Replaces the current process by running the given external command."

This means that when the external program stops, there's no more a ruby script 
to go back to. The usual way to run an external program from a ruby script is 
to use either the backtics operator:

`ruby C:\another_script.rb`

or to use Kernel#system:

system "ruby C:\another_script.rb"

The difference between the two is that the former doesn't display the standard 
output on screen, but returns it as return value of the method call; system, 
instead, displays the standard output normally and returns true if the command 
was executed correctly and false otherwise.

Note that the backtics support string interpolation, so you can write:

`ruby #{path}`

I hope this helps

Stefano