youtube视频下载
wget http://youtube-dl.org/latest/youtube-dl -O /var/www/html/youtube-dl
chmod a+x /usr/local/bin/youtube-dl
常见用法:youtube-dl -h
列出所有格式视频:youtube-dl -F [URL]
下载指定格式视频:youtube-dl --ignore-errors --write-auto-sub -f 22 https://www.youtube.com/watch?v=-Ey4oYSgVxk