If you ever encounter with such similar of an error (in my case it occurred on my Ubuntu 20 distro), you may apply the following process to get a fix.
Reading package lists... Done Building dependency tree Reading state information... Done Calculating upgrade... Done The following packages will be upgraded: apt apt-transport-https apt-utils dpkg libapt-inst2.0 libapt-pkg5.0 ntpdate oracle-java8-installer oracle-java8-set-default thermald 10 upgraded, 0 newly installed, 0 to remove and 0 not upgraded. Need to get 0 B/4,389 kB of archives. After this operation, 8,192 B of additional disk space will be used. Do you want to continue? [Y/n] Y Preconfiguring packages ... dpkg: unrecoverable fatal error, aborting: files list file for package 'linux-generic' is missing final newline E: Sub-process /usr/bin/dpkg returned an error code (2)
Disclaimer: it worked for me, that doesn’t necessary means that would work same for you! However, you may give it a try.
remove or move the missing file
sudo rm /var/lib/dpkg/info/linux-generic.list
Now you can again reinstall it
sudo apt-get install linux-generic --reinstall
sudo dpkg --configure -a sudo apt update sudo apt upgrade
(The later one worked, I suppose the first one should work as well)