Run commands from Ruby (e.g. Rakefile) with real time output and exiting on non-0 exit codes.

Rakefile

desc 'Build'
task :build do
  run("xbuild Project.sln", "Build failed")
  run("nunit-console Tests/bin/Debug/Project-Tests.dll", "Tests failed")
  run("mono Tests/vendor/NSpecRunner.exe Tests/bin/Debug/Project-Tests.dll", "Specs failed")
end

task :default => :demo

# This is the important method
def run(command, message)
  puts "\n==== Run Command: `#{command}` ====\n\n"
  process = IO.popen(command) do |io|
    while line = io.gets
      puts line
    end
    io.close
  end
  fail message if $?.to_i != 0
end