# apt-get update
Hit:1 https://nvidia.github.io/libnvidia-container/stable/ubuntu18.04/amd64 InRelease
Get:2 https://nvidia.github.io/nvidia-container-runtime/stable/ubuntu18.04/amd64 InRelease [1,481 B]
Get:3 https://nvidia.github.io/nvidia-docker/ubuntu18.04/amd64 InRelease [1,474 B]
Get:4 http://dl.google.com/linux/chrome/deb stable InRelease [1,825 B]
Hit:5 https://packages.microsoft.com/repos/vscode stable InRelease
Ign:6http://old-releases.ubuntu.com/ubuntu precise InRelease
Err:4 http://dl.google.com/linux/chrome/deb stable InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 4EB27DB2A3B88B8B
Hit:7 http://ppa.launchpad.net/graphics-drivers/ppa/ubuntu bionic InRelease
Get:9http://old-releases.ubuntu.com/ubuntu precise Release [49.6 kB]
Hit:10 http://ppa.launchpad.net/martinx/xrdp-next/ubuntu bionic InRelease
Get:8 http://old-releases.ubuntu.com/ubuntu precise-updates InRelease [55.7 kB]
Err:8 http://old-releases.ubuntu.com/ubuntu precise-updates InRelease
The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
Get:11 http://old-releases.ubuntu.com/ubuntu precise Release.gpg [198 B]
Ign:11 http://old-releases.ubuntu.com/ubuntu precise Release.gpg
Reading package lists... Done
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error: http://dl.google.com/linux/chrome/deb stable InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 4EB27DB2A3B88B8B
W: GPG error: http://old-releases.ubuntu.com/ubuntu precise-updates InRelease: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository ' http://old-releases.ubuntu.com/ubuntu precise-updates InRelease' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
W: GPG error: http://old-releases.ubuntu.com/ubuntu precise Release: The following signatures were invalid: 630239CC130E1A7FD81A27B140976EAF437D05B5
E: The repository ' http://old-releases.ubuntu.com/ubuntu precise Release' is not signed.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
여러가지 방법을 썼는데 apt-get update가 안된다. 이럴때는 그냥 apt-get 를 초기화 해주는게 좋다.
# dpkg -S apt | grep sources.list
apt: /etc/apt/sources.list.d
apt: /usr/share/doc/apt/examples/sources.list
sources.list 파일 위치를 확인 하고
샘플 파일을 오버라이트 해주면 된다.
# cp /usr/share/doc/apt/examples/sources.list /etc/apt/
이렇게 하면 정상적으로 apt-get update 가 된것을 확인 할 수 있다.