From: John Carter <john.carter@...>
Date: 2008-10-28T09:18:14+09:00
Subject: Re: Join all text files in a folder, with a single line of Ruby 	code

On Sun, 26 Oct 2008, Robert Klemme wrote:

>> File.open("mrg","w"){|f|f.puts Dir['*.txt'].map{|nm|IO.read nm}}
>
> That's vastly inefficient since it reads all the files into memory before 
> writing a single byte.  This is not necessary.  You can at least improve to
>
> File.open("mrg","w"){|f|Dir['*.txt'].each{|nm|f.write(File.read(nm))}}

If we're into fast and ugly...

We need a Ruby interface to Linux "splice"...

   splice()  moves  data  between  two  file  descriptors  without copying
        between kernel address space and user address space.  It  transfers  up
        to  len  bytes  of  data  from  the  file  descriptor fd_in to the file
        descriptor fd_out, where one of the descriptors must refer to a pipe.

See "man splice" for more.


John Carter                             Phone : (64)(3) 358 6639
Tait Electronics                        Fax   : (64)(3) 359 4632
PO Box 1645 Christchurch                Email : john.carter@tait.co.nz
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