From: Josh Cheek <josh.cheek@...>
Date: 2010-05-15T18:27:29+09:00
Subject: Re: difference between $0 and __FILE__

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2010/5/15 Une B=E9vue <unbewusst.sein@google.com.invalid>

>
> i have a script in my HOME/bin :
>
> /Users/yt/bin/path_test.rb
>
> my "HOME/bin" is in the PATH
>
> then, if from this script, i outputs $0 and __FILE__
>
> with :
>
> path_test.rb  i got :
> $0 =3D /Users/yt/bin/path_test.rb
> __FILE__ =3D /Users/yt/bin/path_test.rb
>
>
> and the same outputs with :
> /Users/yt/bin/path_test.rb
>
> why do i have the same outputs in this case ?
>
> in fact i'm looking that because i do have Ruby class extension in a
> subfolder of "HOME/bin", namely :
> HOME/bin/ruby_ext
> where i put my extension for classes of which i could require :
> require "#{File.dirname($0)}/ruby_ext/ansi_color"
>
> what's the best way to require in that case, does i need an "absolute
> path (starting from / ) or not ?
> --
>  =AB Je suis s=FBr que la ga=EEt=E9 ambigu=EB du dr=F4le de gar=E7on qui =
a bu du
> whisky et fait le z=E8bre sur un vieux ca=EFman =E0 No=EBl dans le ca=F1o=
n, a =E9t=E9
> b=E9n=E9fique =E0 l'=E2me du po=E8te bl=EAme, ainsi qu'=E0 son c=9Cur & c=
=E6tera ! =BB
>  (=A9 Jean-Paul Blanc)
>
>

Having a hard time understanding your question. Here are some possible
thoughts:

Difference between $0 and __FILE__
  $ echo 'p $0 , __FILE__' > callee0.rb
  $ echo 'p $0 , __FILE__' > callee1.rb
  $ echo 'p $0 , __FILE__' > callee2.rb
  $ echo '3.times { |i| require "callee#{i}" ; puts }' > main_prog.rb
  $ ruby main_prog.rb
  "main_prog.rb"
  "./callee0.rb"

  "main_prog.rb"
  "./callee1.rb"

  "main_prog.rb"
  "./callee2.rb"


You have the same output because
  The program that was run is the same as the file being checked


How to require relative files:
  http://ruby-doc.org/core/classes/File.html#M002540
  http://tomafro.net/2010/01/tip-relative-paths-with-file-expand-path
  In this case, that probably means you want
File.expand_path('ruby_ext/ansi_color',__FILE__)

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