From: Tobias Reif <tobiasreif@...>
Date: 2002-05-24T20:38:59+09:00
Subject: OS independent scripts, system calls on Windows and Linux

Hi,

I need to script some tools (Xerces, Saxon, Dot, etc).
Since it should be OS independent, and must run unchanged
on at least Linux and any Windows, and should be
very simple, elegant, and quick to write, I choose Ruby over .bat
or .sh scripts.

I'll chain about seven actions, and need to know
if there were errors at any point, or if all went well.

I'm not that experienced yet, so I might miss some obvious
solutions, but AFAICS, the backtick system call
mechanism returns stdout/sterr, but is not OS independent.
If that's so, it should be made OS independent IMHO;
That would be the simplest solution for me.
I don't want to write all the cmd.exe stuff for various Windowses,
each time I write a little script.

The system() method seems to be OS independent, but doesn't
return anything, IIRC. (again: I didn't yet test or read
enough; please correct my assumptions)

Perhaps something like:

commands = # ...
commands.each do |cmd|
   returned = system cmd
   # system (or 'rsys') would return
   #  sterr, or stdout, or nil
   if returned
     case ret
       when Stderr then raise returned
       when Stdout then puts  returned
     end
   end
end

Or is there already a way to write an equiv of the above
which is as short, or shorter?

Ideally there would be
   commands.run
which would do what the above pseudo code outlines.

Tobi

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