From: "Ara.T.Howard" <Ara.T.Howard@...>
Date: 2005-11-08T03:42:05+09:00
Subject: Re: Daemons written in ruby...

On Tue, 8 Nov 2005, Steve [RubyTalk] wrote:

> I've written a simple daemon as a ruby script... it writes all interesting 
> output to a log file and is intended to be a long-running process as opposed 
> to a program which executes only while a user is logged in.
>
> In C I'd have closed stdin, stdout and stderr; dissociate my process from its 
> parent then called fork in order to return 0 indicate successfully starting 
> the daemon.
>
> What is the best way to achieve this in Ruby?  I can achieve the end result I 
> want using nohup, but I'm sure there must be a neater way.

runs any command line as a daemon.  also sets the name that appears in top/ps.

   #! /home/ahoward/bin/ruby
   fork{
     stdin = open '/dev/null', 'r'
     stdout = open '/dev/null', 'w'
     stderr = open '/dev/null', 'w'
     STDIN.reopen stdin
     STDOUT.reopen stdout
     STDERR.reopen stderr
     $0 = ARGV.first || $0
     fork{
       command = ARGV.join ' '
       system(command) ? exit : abort
     } and exit!
   }

-a
-- 
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| email :: ara [dot] t [dot] howard [at] noaa [dot] gov
| phone :: 303.497.6469
| anything that contradicts experience and logic should be abandoned.
| -- h.h. the 14th dalai lama
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