How to use the npm-which.sync function in npm-which

['git', 'grunt', 'travis'].forEach(function(module) {
  try {
    which(module);
  } catch (e) {
    console.log('ERROR: You need ' + module + ' installed and available in your PATH.');
    process.exit(0);
  }
});

if (program.version) {
    console.log(pkg.version)
    process.exit()
  }

  if (program.help) {
    displayHelp(pkg.name)
    process.exit()
  } else {
    displayHelp(pkg.name)
    process.exit(1)
  }
}

try {
  npmWhich.sync(process.argv[2], {cwd: process.cwd()})
} catch (err) {
  console.log(err.message)
  process.exit(1)
}

npmExec.spawn(process.argv[2], process.argv.slice(3), {stdio: 'inherit'})
  .on('error', function (err) {
    console.error(err.stack)
  })
  .on('close', function (code) {
    process.exit(code)
  })

function displayHelp (name) {
  console.log([
    'Usage: ' + name + ' command [...args]',