I've only recently switched to Ubuntu 18.04 from Windows 10, maybe I am missing something I can't understand. I've already searched most of the previously asked question on the topic, but with no luck.
Upon executing sudo apt-get update, this happens:
Hit:1 http://ro.archive.ubuntu.com/ubuntu bionic InRelease
Ign:2 http://dl.google.com/linux/chrome/deb stable InRelease
Hit:3 http://ro.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:4 http://ro.archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:5 http://security.ubuntu.com/ubuntu bionic-security InRelease
Hit:6 http://dl.google.com/linux/chrome/deb stable Release
sh: 1: /usr/lib/cnf-update-db: not found
Reading package lists... Done
E: Problem executing scripts APT::Update::Post-Invoke-Success 'if /usr/bin/test -w /var/lib/command-not-found/ -a -e /usr/lib/cnf-update-db; then /usr/lib/cnf-update-db > /dev/null; fi'
E: Sub-process returned an error code
Edit: the contents of apt policy command-not-found:
command-not-found:
Installed: 18.04.5
Candidate: 18.04.5
Version table:
*** 18.04.5 500
500 http://ro.archive.ubuntu.com/ubuntu bionic-updates/main amd64 Packages
500 http://ro.archive.ubuntu.com/ubuntu bionic-updates/main i386 Packages
100 /var/lib/dpkg/status
18.04.4 500
500 http://ro.archive.ubuntu.com/ubuntu bionic/main amd64 Packages
500 http://ro.archive.ubuntu.com/ubuntu bionic/main i386 Packages
sudo apt-get -f install also didnt help, with the result being:
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
libfwup1 libwayland-egl1-mesa linux-headers-5.3.0-28 linux-headers-5.3.0-28-generic linux-image-5.3.0-28-generic
linux-modules-5.3.0-28-generic linux-modules-extra-5.3.0-28-generic
Use 'sudo apt autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
I'm not proficient with Ubuntu, and I'm afraid I might delete or modify a critical file which could potentially cause more errors
