From: Ross Bamford <rossrt@...>
Date: 2006-03-24T06:03:49+09:00
Subject: Re: Directory structure of a Ruby installation, including the	paths that should be set, etc.

On Fri, 2006-03-24 at 05:31 +0900, Randy Kramer wrote:
> Restart:
> 
> For a variety of reasons, I'm trying to get a better understanding of how a 
> Ruby installation is laid out on disk.  Maybe the best way to explain what I 
> mean is by giving some of the specific questions I have.  (Maybe these are 
> not so much Ruby specific, but maybe generic to a typical language install.)  
> 

I think Ruby generally follows the standard Linux/FHS layout, together
with layout used by other languages (I know Perl has site_perl, for
example).

> BTW, this is for a Linux installation.
> 
> Statements and questions intermixed:
> 
>    * I installed Ruby 1.8.4 by compiling from the source tarball, and started 
> by untar-ing it in, essentially, my home directory.  
> 
>       * Was that an appropriate place to untar?  Does it matter much, or at 
> all?  (I mean, as long as I have the necessary permissions to untar and 
> access the files.)
> 

I don't think it really matters, but if I'm installing something
system-wide I tend to keep the source in /usr/local/src , while if I'm
installing for just me I keep it in ~/src.

>    * The ruby executable is installed in /usr/local/bin/ruby, and a bunch 
> of .rb files are installed in /usr/local/lib/ruby/1.8/.  I didn't have any 
> choice in the matter, so I assume that's a good location.
> 

It's the default (and standard) location. For a systemwide install I'd
call it 'the right location', but bear in mind that you can change it
during the configure step (try passing --help to the ruby configure
script). I (and I guess many others) have a site-wide Ruby 1.8 install,
and a 1.9 snapshot installed in my home directory, also with a different
program suffix (ruby9, irb9, ri9, etc) which is handled with options to
the configure script.

>    * Many, maybe all, of those same .rb files are in what I'll call my install 
> directory (tree) (in my home directory).  Now that ruby is installed can I 
> delete all that stuff in my home directory (that came from untar-ing the 
> tarball)?
> 

I guess so, but I wouldn't. I guess if you're absolutely sure you won't
want to do a quick rebuild, or look something up in the source, then you
could delete them if you wished.

>    * If I go to install another "library" (is that the right word for 
> those .rb files), specifically for the tkHTML widget, I presume I should 
> install that in the /usr/local/lib/ruby/1.8/ directory (or a subdirectory)?
> 

That's not recommended practice - that directory holds ruby and the
standard library, additional stuff is usually placed
in /usr/local/lib/ruby/site_ruby/1.8 I think. Most libraries come with a
setup.rb that'll install there automatically.

>    * When I do a require, like require 'tk', the tk.rb file is looked for 
> in /usr/local/lib/ruby/1.8/?  
> 

$ ruby -e 'p $LOAD_PATH'
["/usr/local/lib/ruby/site_ruby/1.8",
 "/usr/local/lib/ruby/site_ruby/1.8/i686-linux",
 "/usr/local/lib/ruby/site_ruby", 
 "/usr/local/lib/ruby/1.8",
 "/usr/local/lib/ruby/1.8/i686-linux", 
 "."]

>    * If tk.rb were in some subdirectory of /usr/local/lib/ruby/1.8/ (say sub, 
> for example), then the require statement to have it loaded would be require 
> 'sub/tk'?
> 

Yes. I think 'require' paths are tried relative to the paths in
$LOAD_PATH, in order.

>    * As long as all of my library .rbs are in the /usr/local/lib/ruby/1.8/ 
> tree, I don't have to set the RUBYLIB environment variable?
> 

Not as far as I'm aware, I don't think I ever have.

Hope that helps,
-- 
Ross Bamford - rosco@roscopeco.REMOVE.co.uk