message: Add executable permissions check for tweego on Unix systems
diff: @@ -9,6 +9,7 @@ utils.logClear()
  const tweego = path.resolve(utils.twineFolder, 'tweego')
  +// Verify correct tweego installation
  if (!fs.existsSync(tweego) && !fs.existsSync(`${tweego}.exe`)) {
  utils.logError('Cannot find path to tweego.')
  utils.logError('Perhaps tweego has not been downloaded.')
  @@ -16,6 +17,16 @@ if (!fs.existsSync(tweego) && !fs.existsSync(`${tweego}.exe`)) {
  process.exit(1)
  }
  +// Verify executable permissions on unix systems.
  +if (['linux', 'darwin'].includes(process.platform)) {
  + try {
  + fs.accessSync(tweego, fs.constants.X_OK)
  + } catch (err) {
  + utils.logError(`${tweego} does not have permissions to execute.
  + If you are on a Unix-based system you can grant permissions with 'chmod +x ${tweego}'`)
  + process.exit(1)
  + }
  +}
  // Extract extra arguments.
  const [, , ...flags] = process.argv
  