From: Joel VanderWerf <joelvanderwerf@...>
Date: 2010-07-02T02:03:15+09:00
Subject: Re: Fast searching of large files

Michael Fellinger wrote:
> On Thu, Jul 1, 2010 at 6:47 PM, Stuart Clarke
> <stuart.clarke1986@gmail.com> wrote:
>> Hey all,
>>
>> Could anyone advise me on a fast way to search a single, but very large
>> file (1Gb) quickly for a string of text? Also, is there a library to
>> identify the file offset this string was found within the file?
> 
> You can use IO#grep like this:
> File.open('qimo-2.0-desktop.iso', 'r:BINARY'){|io|
> io.grep(/apiKey/){|m| p io.pos => m } }
> 
> The pos is the position the match ended

Actually, pos will be the position of the end of the line on which the 
match was found, because #grep works line by line.