From: Rob Biedenharn <Rob@...>
Date: 2007-08-22T20:50:14+09:00
Subject: Re: tail, start reading at EOF

On Aug 22, 2007, at 6:27 AM, Rebhan, Gilbert wrote:
> -----Original Message-----
> From: Bertram Scharpf [mailto:lists@bertram-scharpf.de]
> Sent: Wednesday, August 22, 2007 12:14 PM
> To: ruby-talk ML
> Subject: Re: tail, start reading at EOF
>
> /*
> Hi,
>
> Am Mittwoch, 22. Aug 2007, 18:20:12 +0900 schrieb Rebhan, Gilbert:
>> how to alter tail function to start at the end
>> of the file, not reading the lines already existing in file ? =
>
>   file.seek 0, IO::SEEK_END
> */
>
> thanks, with your pointer and an older post by Robert Klemme
> i have a working solution now =
>
> def tail(file, interval=1)
>    raise "Illegal interval #{interval}" if interval < 0
>
>    File.open(file) do |io|
>       io.seek 0, IO::SEEK_END
>      loop do
>        while ( line = io.gets )
>          puts line
>        end
>        # uncomment next to watch what is happening
>        puts "-"
>        sleep interval
>      end
>    end
> end
>
> Anything to improve ?
>
> Regards, Gilbert

gem install file-tail

Then look at the rdoc for it.  There's an example that does an  
implementation of the Unix tail command.  It's a lot more capable  
that what you have here, but if you wanted to start some number of  
lines before the EOF, the file-tail gem is really what you want.

-Rob

Rob Biedenharn		http://agileconsultingllc.com
Rob@AgileConsultingLLC.com