Recently had a very frustrating error on Proxmox (Debian) while trying to upgrade to R 3.4.2

The following packages have unmet dependencies:
 r-base-core : Depends: libjpeg8 (>= 8c) but it is not installable
               Depends: libpng12-0 (>= 1.2.13-4) but it is not installable
               Depends: libreadline6 (>= 6.0) but it is not installable
               Recommends: r-recommended but it is not going to be installed
               Recommends: r-base-dev but it is not going to be installed
               Recommends: r-doc-html but it is not going to be installed

The solution was to add a source

>nano /etc/apt/sources.list

Then I added a line

deb http://mirrors.kernel.org/ubuntu trusty main

Alright, now the

apt-get update

…

Damn

W: GPG error: http://mirrors.kernel.org/ubuntu trusty Release: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32
W: The repository 'http://mirrors.kernel.org/ubuntu trusty Release' is not signed.

Alright…need to add the keys.

>gpg --keyserver keyserver.ubuntu.com --recv-keys NO_PUBKEY 40976EAF437D05B5 NO_PUBKEY 3B4FE6ACC0B21F32
>gpg --export --armor 40976EAF437D05B5 | sudo apt-key add -
>gpg --export --armor 3B4FE6ACC0B21F32 | sudo apt-key add -

Uggggh, finally. Now we can install r-base-core and r-base-dev through the standard apt-get install and use RStudio v1.1. Woooo!!!!