From: Logan Capaldo <logancapaldo@...>
Date: 2006-04-11T14:46:38+09:00
Subject: Re: App not waiting for popen to finish


On Apr 11, 2006, at 1:31 AM, |MKSM| wrote:

> Hello,
>
> I'm using 'wget' to download a few files and then tar them up. I'm
> using popen to make calls to wget and tar. Problem is that it tries to
> call tar right after the wget call. I need to wait for wget to finish.
> Here is what i've got so far.
>
> categories = [...]
>
> categories.each_with_index { |url,i|
>   IO.popen("wget -r -np -l 0 -w 4 #{url}")
>   IO.popen("tar -zcf public_html/category_#{i}.tar.gz files")
> }
>
> Thanks in advance.
>
> Ricardo
>

The solution would be to do

IO.popen("...")
Process.wait

However since you aren't apparently even using the IO capabilities of  
popen, why not simply make use of system? It will automatically wait  
for the process to exit
e.g.

system("wget -r -np -l 0 -w 4 #{url}")
  Of course if the only reason you are using IO.popen is to prevent  
output to the console you can do
system("wget -r -np -l 0 -w 4 #{url} 2>&1 >/dev/null")
Or even:

Process.wait Process.fork { STDOUT.reopen("/dev/null", "w");  
STDERR.reopen("/dev/null", "w"); exec("wget -r -np -l 0 -w 4 #{url}") }