安装：npm install -g gitbook-cli
生成pdf：gitbook pdf
生成pdf时报错：
EbookError: Error during ebook generation: 'ebook-convert' is not recognized as an internal or external command, operable program or batch file.
...............
[25670:25670:0526/160121.792008:ERROR:zygote_host_impl_linux.cc(89)] Running as root without --no-sandbox is not supported. See https://crbug.com/638180.
解决办法：安装calibre： apt install -y calibre