From: optman <optman@...>
Date: 2007-09-07T14:45:06+09:00
Subject: Re: Where is the definition of File.read()?

On 9 7 ,   1 15 , rio4ruby <Christopher.Kleck...@gmail.com> wrote:
> On Sep 6, 9:41 pm, optman <opt...@gmail.com> wrote:
>
> > On 9 7 ,   1 24 , John Joyce <dangerwillrobinsondan...@gmail.com>
> > wrote:
>
> > I have seen a line of code like
>
> > put( File.read(sourceFile),targetFile)
>
> > if File.read() return the entire file content, what if sourceFile is a
> > large file?
>
> Then you are in trouble if you use File.read(). From your example I
> can don't know what the method #put does, but one might logically
> surmise that its function is to put a string (the output of File.read)
> into targetFile.
>
> Reading a file into a string and then writing that string to a file is
> not a good solution for large files. The module ::FileUtils contains a
> method #cp which very efficiently (by ruby standards) copies one file
> to another -- without requiring that the entire contents of the source
> file be copied into memory first.
>
> Rio (http://rio.rubyforge.org) will also copy a file without requiring
> the source file being read into memory first:
>
>   rio('sourceFile') > rio('targetFile')

Method #put is from Capistrano, which upload file to remote server by
ssh. I found it don't work correctly with large file, maybe this is
the reason.