code: function _run(cmd, done) {
    var child = exec(cmd, function (error, stdout, stderr) {
      if(stdout) console.log('O: ' + stdout);
      if(stderr) console.log('E: ' + stderr);
      if (error !== null) {
        console.log('exec error: ' + error);
        console.log('error code: ' + error.code);
        done(error);
      } else {
        done();
      }
      return;
    });
    return child.pid;
  }
docs: /*
  Run a system command 'cmd'