由于debian9 停止維護(hù)，目前可用的軟件源如下：
deb http://archive.debian.org/debian/ stretch main contrib non-free
deb-src http://archive.debian.org/debian/ stretch main contrib non-free
deb http://archive.debian.org/debian-security/ stretch/updates main contrib non-free
deb-src http://archive.debian.org/debian-security/ stretch/updates main contrib non-free
deb http://archive.debian.org/debian/ stretch-backports main contrib non-free
1.設(shè)置軟件源
cat >/etc/apt/sources.list<<EOF
deb http://archive.debian.org/debian/ stretch main contrib non-free
deb-src http://archive.debian.org/debian/ stretch main contrib non-free
deb http://archive.debian.org/debian-security/ stretch/updates main contrib non-free
deb-src http://archive.debian.org/debian-security/ stretch/updates main contrib non-free
deb http://archive.debian.org/debian/ stretch-backports main contrib non-free
EOF
2.更新軟件源： apt update -y
3.提示gpg證書錯(cuò)誤處理
報(bào)錯(cuò)信息：
W: GPG error: http://archive.debian.org/debian stretch-backports InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 648ACFD622F3D138 NO_PUBKEY 0E98404D386FA1D9
安裝需要的依賴和軟件：
apt-get install software-properties-common dirmngr -y
添加gpg證書驗(yàn)證：
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys <PUBKEY>
<PUBKEY2>
apt-key adv --keyserver keyserver.ubuntu.com --recv-keys 648ACFD622F3D138 0E98404D386FA1D9
4.再次執(zhí)行更新軟件源：apt update -y
