old_contents: #!/usr/bin/env node
  
  // maintainer note - x.y.z-ab version in package.json -> x.y.z
  var version = require('./package').version.replace(/-.*/, '')
  
  var fs = require('fs')
  var os = require('os')
  var path = require('path')
  var extract = require('extract-zip')
  var download = require('electron-download')
  
  var installedVersion = null
  try {
    installedVersion = fs.readFileSync(path.join(__dirname, 'dist', 'version'), 'utf-8').replace(/^v/, '')
  } catch (err) {
    // do nothing
  }
  
  var platform = process.env.npm_config_platform || os.platform()
  
  function onerror (err) {
    throw err
  }
  
  var paths = {
    darwin: 'dist/Electron.app/Contents/MacOS/Electron',
    freebsd: 'dist/electron',
    linux: 'dist/electron',
    win32: 'dist/electron.exe'
  }
  
  if (!paths[platform]) throw new Error('Electron builds are not available on platform: ' + platform)
  
  if (installedVersion === version && fs.existsSync(path.join(__dirname, paths[platform]))) {
    process.exit(0)
  }
  
  // downloads if not cached
  download({
    version: version,
    platform: process.env.npm_config_platform,
    arch: process.env.npm_config_arch,
    strictSSL: process.env.npm_config_strict_ssl === 'true',
    quiet: ['info', 'verbose', 'silly', 'http'].indexOf(process.env.npm_config_loglevel) === -1
  }, extractFile)
  
  // unzips and makes path.txt point at the correct executable
  function extractFile (err, zipPath) {
    if (err) return onerror(err)
    fs.writeFile(path.join(__dirname, 'path.txt'), paths[platform], function (err) {
      if (err) return onerror(err)
      extract(zipPath, {dir: path.join(__dirname, 'dist')}, function (err) {
        if (err) return onerror(err)
      })
    })
  }
  
new_contents: #!/usr/bin/env node
  
  // maintainer note - x.y.z-ab version in package.json -> x.y.z
  var version = require('./package').version.replace(/-.*/, '')
  
  var fs = require('fs')
  var os = require('os')
  var path = require('path')
  var extract = require('extract-zip')
  var download = require('electron-download')
  
  var installedVersion = null
  try {
    installedVersion = fs.readFileSync(path.join(__dirname, 'dist', 'version'), 'utf-8').replace(/^v/, '')
  } catch (err) {
    // do nothing
  }
  
  var platform = process.env.npm_config_platform || os.platform()
  
  function onerror (err) {
    throw err
  }
  
  var paths = {
    darwin: 'dist/Electron.app/Contents/MacOS/Electron',
    freebsd: 'dist/electron',
    linux: 'dist/electron',
    win32: 'dist/electron.exe'
  }
  
  if (!paths[platform]) throw new Error('Electron builds are not available on platform: ' + platform)
  
  if (installedVersion === version && fs.existsSync(path.join(__dirname, paths[platform]))) {
    process.exit(0)
  }
  
  // downloads if not cached
  download({
    version: version,
    platform: process.env.npm_config_platform,
    arch: process.env.npm_config_arch,
    strictSSL: process.env.npm_config_strict_ssl === 'true',
    quiet: ['info', 'verbose', 'silly', 'http'].indexOf(process.env.npm_config_loglevel) === -1
  }, extractFile)
  
  // unzips and makes path.txt point at the correct executable
  function extractFile (err, zipPath) {
    if (err) return onerror(err)
    extract(zipPath, {dir: path.join(__dirname, 'dist')}, function (err) {
      if (err) return onerror(err)
      fs.writeFile(path.join(__dirname, 'path.txt'), paths[platform], function (err) {
        if (err) return onerror(err)
      })
    })
  }
  
subject: Write path.txt after extraction