From: Rick DeNatale <rick.denatale@...>
Date: 2008-02-12T21:06:01+09:00
Subject: Re: how to say # in ruby

On 2/11/08, Tim Hunter <rmagick@gmail.com> wrote:
> Robert Klemme wrote:
>
> > I'm not sure what you're at here.  You posted code from the Ruby
> > interpreter but the magical bit of shebang is done by the shell or OS
> > not Ruby.
>
> Bear in mind that if the shell started the program and the program
> specified on the shebang line wasn't the ruby interpreter, the code
> quoted above doesn't run.
>
> Since it is running, somehow the ruby interpreter has been started and
> given a file containing text that may or may not actually be Ruby code.
> This could happen if you started ruby by explicitly executing the "ruby"
> command, or if you're running on Windows where there is no shell to do
> shebang interpreting for you.
>
> That bit of code inspects the shebang line and, if the word "ruby"
> doesn't appear on the line, it tries to execute what it assumes is a
> program.

Actually what that code does is:

If the first line is a shebang
  if it doesn't contain 'ruby' somewhere
     extract the path which it seems to be wanting to run
     produce a fatal error
  else
     extract any arguments for the ruby command
     continue to process.
  end
end

So it is trying to avoid accidentially running, say a bash or perl
script using the ruby interpreter.

-- 
Rick DeNatale

My blog on Ruby
http://talklikeaduck.denhaven2.com/