From: Robert La Ferla <robertlaferla@...>
Date: 2007-04-16T09:30:50+09:00
Subject: Re: executing a system command and stopping it after a specified duration?


On Apr 15, 2007, at 3:39 AM, Stefan Mahlitz wrote:

>
> If you want to read from '/dev/video' you could combine  
> james.d.masters
> and Dan Zwells suggestions - but using system or `
>
> require "timeout"
> begin
>   Timeout::timeout(600) do
>     system("cat /dev/video > test.mpg")
>     # `cat /dev/video > test.mpg`
>   end
> rescue Timeout::Error
>   puts("Done")
> end
>
> or
>
> require "timeout"
> begin
>   Timeout::timeout(600) do
>     File.open("/dev/video", "rb") do |input|
>       File.open("test.mpg", "wb") do |output|
>         input.each_byte {|byte| output.putc(byte)}
>       end
>     end
>   end
> rescue Timeout::Error
>   puts("Done")
> end

Thanks.

A couple of issues:

1.  The time out is working but the "cat" process is not terminated.   
I tried both system(cmd) and `#{cmd}`.

2.  I wonder if Ruby is fast enough to read /dev/video and dump it to  
a file without a delay.  Imagine if this is running for a couple of  
hours...


BTW - My configuration is:

  % ruby --version
ruby 1.8.5 (2007-03-13 patchlevel 35) [i386-linux]

Fedora Linux 2.6.20-1.2933.fc6