From: Ted Flethuseo <flethuseo@...>
Date: 2010-07-22T23:08:34+09:00
Subject: Re: finding last line in a file

Robert Klemme wrote:
> On 07/22/2010 07:10 AM, Urabe Shyouhei wrote:
>> (2010/07/22 14:08), Urabe Shyouhei wrote:
>>> Take a look at the doc for File.readline.
>>
>> Oops... typo.  I meant readlines.  With it you can do something like
>> File.readlines(f).last
> 
> This is as inefficient as using File.foreach because it will read the
> whole file.  I believe Ted was looking for a more efficient solution.
> 
> Ted, if you want to do this in Ruby and not resort to tail you can use
> IO#seek to seek to the end of the file and read backwards until you have
> read more than one line.
> 
> Kind regards
> 
>   robert

Interesting, the problem is how to find how far back I need to go in the 
seek (automatically of course)

  f = File.new("testfile")
  f.seek(-13, IO::SEEK_END)   #=> 0
  f.readline                  #=> "And so on...\n"

Ted.
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