Jetson AGX Xavier更换apt-get源

使用apt-get安装时，会很慢，更换了国内的源后，就可以解决这个问题了。

1. 备份sources.list文件

sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak

2. 打开sources.list文件

sudo gedit /etc/apt/sources.list

3. 删除原内容，添加下列内容

#清华源
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-updates main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-security main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic-backports main restricted universe multiverse
deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic main universe restricted
deb-src http://mirrors.tuna.tsinghua.edu.cn/ubuntu-ports/ bionic main universe restricted

#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

这两个源都可以用，我都试过，感觉中科大源速度更快。

4. 更新

保存sources.list文件后需要更新apt-get。

sudo apt-get update

更新完成后就可以正常使用了。