From: nobu.nokada@...
Date: 2002-05-29T18:58:35+09:00
Subject: Re: OS independent scripts, system calls on Windows and Linux

Hi,

At Wed, 29 May 2002 18:04:00 +0900,
Tobias Reif wrote:
> I want to get what the command returns; if possible, I'd like to know
> if there was any of stdout, stderr, or both, or nothing, so I can
> choose what to do with the returned strings/objetcs, or if to raise an
> error. Would that be feasible?
> 
> Syntax *could* look like (this probably has errors)

I'm thinking like this:

  currthr = Thread.current
  ['this -x -y','that -a -b'].each do |cmd|
    process = Process.start(cmd, :stdout=>true, :stderr=>true)
    # pipes stdout and stderr,
    # would raise when couldn't run `cmd'.
    Thread.new(process.stderr) do |f|
      # if something from stderr, it's error.
      currthr.raise error if error = f.read
    end
    puts process.stdout
    process.wait.exitcode == 0 or raise
  end


BTW, why do you need to use stderr to detect errors?  Your
commands don't return exit code?

At Fri, 24 May 2002 22:19:59 +0900,
Tobias Reif wrote:
> I need a very simple way to issue the list of commands, in a very
> simple and highly platform independent way.

If you just need to run successive commands only when preceding
commands succeeded, this doesn't help?

<<CMDS.split("\n").each {|cmd| system(cmd) or break}
this -x -y
that -a -b
CMDS

-- 
Nobu Nakada