From: "Einar Magnús Boson" <einarmagnus@...>
Date: 2008-12-17T15:02:05+09:00
Subject: Re: ruby way of dumping file


On 17.12.2008, at 05:42 , The Higgs bozo wrote:

> Joshua Ball wrote:
>> Hi,
>> Can someone give me a cleaner, more rubyesque (even correct) way of
>> printing
>> out the first 20 bytes of a file? My solution doesn't feel right.
>
> print File.read(ARGV.first)[0...20]
> --  
> Posted via http://www.ruby-forum.com/.
>


Doesn't that read the entire file before extracting the first 20  
bytes? Seems silly to me.

rather something like this:

open ARGV.first, "rb" do |f|
	read = ""
	begin
		read += f.read(20)
	end while read.size < 20  && !f.eof?
	p read[0...20]
end

although I suppose this would work too:

p open(ARGV[0], "rb"){|f|f.read(20)}

but I don't think read(20) is guaranteed to read 20 bytes but maybe  
that is just in sockets.

einarmagnus