jetson xavier nx下换国内源，步骤如下：
#!/bin/bash
cp /etc/apt/sources.list /etc/apt/sources.list.bak
#换源
echo "#中科大源
deb http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic main universe restricted
deb-src http://mirrors.ustc.edu.cn/ubuntu-ports/ bionic main universe restricted" >/etc/apt/sources.list