Gfilui

On Ubuntu 18.04 I am getting this when I want to install the recommended Nvidia driver.

sudo apt install nvidia-340
Reading package lists... Done
Building dependency tree 
Reading state information... Done
The following packages were automatically installed and are no longer required:
 libargtable2-0 libass5 libavcodec-ffmpeg56 libavdevice-ffmpeg56
 libavfilter-ffmpeg5 libavformat-ffmpeg56 libavresample-ffmpeg2
 libavutil-ffmpeg54 libbluray1 libboost-random1.58.0 libboost-regex1.58.0
 libboost-thread1.58.0 libcryptopp-dev libethereum libfdk-aac0 libjsoncpp1
 libjsonrpccpp-client0 libjsonrpccpp-common0 libjsonrpccpp-server0
 libleveldb1v5 libmicrohttpd10 libmicrohttpd12 libnvidia-common-396
 libopencv-core2.4v5 libopencv-imgproc2.4v5 libopenjpeg5 libpostproc-ffmpeg53
 libschroedinger-1.0-0 libsdl-ttf2.0-0 libswresample-ffmpeg1
 libswscale-ffmpeg3 libtbb2 libva1 libx264-148 libx265-79 miniupnpc
 nvidia-kernel-common-396 nvidia-kernel-source-396 nvidia-prime php7.1-common
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
 nvidia-340
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
2 not fully installed or removed.
Need to get 0 B/51,9 MB of archives.
After this operation, 274 MB of additional disk space will be used.
(Reading database ... 345463 files and directories currently installed.)
Preparing to unpack .../nvidia-340_340.107-0ubuntu0~gpu18.04.1_amd64.deb ...
diversion of /usr/lib/x86_64-linux-gnu/libGL.so.1 to /usr/lib/x86_64-linux-gnu/libGL.so.1.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libGL.so.1 to /usr/lib/x86_64-linux-gnu/libGL.so.1.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libGL.so.1 to /usr/lib/i386-linux-gnu/libGL.so.1.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libGL.so.1 to /usr/lib/i386-linux-gnu/libGL.so.1.distrib by nvidia-340'
diversion of /usr/lib/x86_64-linux-gnu/libGL.so to /usr/lib/x86_64-linux-gnu/libGL.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libGL.so to /usr/lib/x86_64-linux-gnu/libGL.so.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libGL.so to /usr/lib/i386-linux-gnu/libGL.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libGL.so to /usr/lib/i386-linux-gnu/libGL.so.distrib by nvidia-340'
diversion of /usr/lib/x86_64-linux-gnu/libEGL.so.1 to /usr/lib/x86_64-linux-gnu/libEGL.so.1.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libEGL.so.1 to /usr/lib/x86_64-linux-gnu/libEGL.so.1.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libEGL.so.1 to /usr/lib/i386-linux-gnu/libEGL.so.1.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libEGL.so.1 to /usr/lib/i386-linux-gnu/libEGL.so.1.distrib by nvidia-340'
diversion of /usr/lib/x86_64-linux-gnu/libEGL.so to /usr/lib/x86_64-linux-gnu/libEGL.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libEGL.so to /usr/lib/x86_64-linux-gnu/libEGL.so.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libEGL.so to /usr/lib/i386-linux-gnu/libEGL.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libEGL.so to /usr/lib/i386-linux-gnu/libEGL.so.distrib by nvidia-340'
diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so to /usr/lib/x86_64-linux-gnu/libGLESv2.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so to /usr/lib/x86_64-linux-gnu/libGLESv2.so.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libGLESv2.so to /usr/lib/i386-linux-gnu/libGLESv2.so.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libGLESv2.so to /usr/lib/i386-linux-gnu/libGLESv2.so.distrib by nvidia-340'
diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so.2 to /usr/lib/x86_64-linux-gnu/libGLESv2.so.2.distrib by nvidia-340
Removing 'diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so.2 to /usr/lib/x86_64-linux-gnu/libGLESv2.so.2.distrib by nvidia-340'
diversion of /usr/lib/i386-linux-gnu/libGLESv2.so.2 to /usr/lib/i386-linux-gnu/libGLESv2.so.2.distrib by nvidia-340
Removing 'diversion of /usr/lib/i386-linux-gnu/libGLESv2.so.2 to /usr/lib/i386-linux-gnu/libGLESv2.so.2.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libGL.so.1 to /usr/lib/x86_64-linux-gnu/libGL.so.1.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libGL.so.1 to /usr/lib/i386-linux-gnu/libGL.so.1.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libGL.so to /usr/lib/x86_64-linux-gnu/libGL.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libGL.so to /usr/lib/i386-linux-gnu/libGL.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libEGL.so.1 to /usr/lib/x86_64-linux-gnu/libEGL.so.1.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libEGL.so.1 to /usr/lib/i386-linux-gnu/libEGL.so.1.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libEGL.so to /usr/lib/x86_64-linux-gnu/libEGL.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libEGL.so to /usr/lib/i386-linux-gnu/libEGL.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so to /usr/lib/x86_64-linux-gnu/libGLESv2.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libGLESv2.so to /usr/lib/i386-linux-gnu/libGLESv2.so.distrib by nvidia-340'
Adding 'diversion of /usr/lib/x86_64-linux-gnu/libGLESv2.so.2 to /usr/lib/x86_64-linux-gnu/libGLESv2.so.2.distrib by nvidia-340'
Adding 'diversion of /usr/lib/i386-linux-gnu/libGLESv2.so.2 to /usr/lib/i386-linux-gnu/libGLESv2.so.2.distrib by nvidia-340'
Unpacking nvidia-340 (340.107-0ubuntu0~gpu18.04.1) ...
dpkg: error processing archive /var/cache/apt/archives/nvidia-340_340.107-0ubuntu0~gpu18.04.1_amd64.deb (--unpack):
 trying to overwrite '/lib/udev/rules.d/71-nvidia.rules', which is also in package nvidia-kernel-common-396 396.45-0ubuntu0~gpu18.04.2
dpkg-deb: error: paste subprocess was killed by signal (Broken pipe)
Errors were encountered while processing:
 /var/cache/apt/archives/nvidia-340_340.107-0ubuntu0~gpu18.04.1_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

How do I get past this?

Press Ctrl+Alt+T and do:

sudo dpkg -i --force-overwrite /var/cache/apt/archives/nvidia-340_340.107-0ubuntu0~gpu18.04.1_amd64.deb

This will resolve "the trying to overwrite error" with the mighty force of dpkg. :)

Then run:

sudo apt -f install

to fix if any broken packages.