gistfile1.txt

    cat packages/flutter/doc/styles.html doc/_analytics.html > /tmp/_header.html

Became:

      flutter_styles = checkout.join('packages', 'flutter', 'doc',
'styles.html')
      analytics = checkout.join('doc', '_analytics.html')
      header_contents = '\n'.join([
        api.file.read('Read styles.html', flutter_styles),
        api.file.read('Read _analytics.html', analytics),
      ])
      header = temp_dir.join('_header.html')
      api.file.write('Write _header.html', header)