下载校验与命令行
SHA256
f730be589aa1ba923ebe6eca573fa66d09ba14c4c104da2c329df652d42aff11
curl -O https://releases.ubuntu.com/18.04/ubuntu-18.04.6-live-server-amd64.iso
# 校验文件完整性
md5sum ubuntu-18.04.6-live-server-amd64.iso # 期望