From: Nobuyoshi Nakada <nobu@...>
Date: 2006-12-21T09:55:01+09:00
Subject: Re: Kernel#system bug?

Hi,

At Thu, 21 Dec 2006 06:45:06 +0900,
Charlton wrote in [ruby-talk:230639]:
> Program:
> 
> Dir.mkdir("bug") if !FileTest.exists?("bug")
> File.open("bug/bugfile", "w") { |file|
>     file << "Bug!"
> }
> Dir.chdir("bug")
> 
> puts "without semi-colon"
> IO.popen("env").readlines.each do |entry|
>     puts entry if entry =~ /PWD/
> end
> 
> puts "with semi-colon"
> IO.popen("env;").readlines.each do |entry|
>     puts entry if entry =~ /PWD/
> end
> 
> Output:
> 
> without semi-colon
> PWD=/user/blah/tests/ruby
> with semi-colon
> PWD=/user/blah/tests/ruby/bug

It is natural result.
PWD is not set by OS automatically, but set by sh.

You should use getcwd() in C or Dir.pwd in ruby instead of
relying on $PWD.

-- 
Nobu Nakada