# make sure your current Ubuntu Linux system is up to date
sudo apt update
sudo apt upgrade
sudo apt dist-upgrade
# remove cruft
sudo apt autoremove
# update manager core
sudo apt install update-manager-core
# upgrade
sudo do-release-upgrade
# REBOOT WSL FROM POWERSHELL
wsl -l -v
wsl --shutdown
# clean up, freshen up
sudo dnf clean all
sudo dnf upgrade --refresh
sudo dnf install dnf-plugin-system-upgrade
# download new version
sudo dnf system-upgrade download --releasever=39
# this is a VM, no need to reboot
export DNF_SYSTEM_UPGRADE_NO_REBOOT=1
# utilize the virtual reboot
sudo -E dnf system-upgrade reboot
# upgrade
sudo -E dnf system-upgrade upgrade
# REBOOT WSL FROM POWERSHELL
wsl -l -v
wsl -t Fedora
# The general procedure here is adapted from the 7->8 guide here. https://www.tecmint.com/upgrade-centos-7-to-centos-8/
#
# It is a curated list of my bash history. I entered other commands so hopefully I got the right ones here.
yum upgrade
## virtual reboot
wsl -l -v
wsl -t CentOS
dnf install epel-release
dnf install rpmconf
dnf install yum-utils
rpmconf -a # answer "n" to both things
package-cleanup --leaves
package-cleanup --orphans
dnf install http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/Packages/centos-stream-repos-9.0-20.el9.noarch.rpm http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/Packages/centos-stream-release-9.0-20.el9.noarch.rpm http://mirror.stream.centos.org/9-stream/BaseOS/x86_64/os/Packages/centos-gpg-keys-9.0-20.el9.noarch.rpm
curl -O https://dl.fedoraproject.org/pub/epel/epel-release-latest-9.noarch.rpm
curl -O https://dl.fedoraproject.org/pub/epel/epel-next-release-latest-9.noarch.rpm
rpm -Uvh *.rpm
yum update
dnf clean all
rpm -e `rpm -q kernel`
dnf -y --releasever=9 --allowerasing --setopt=deltarpm=false distro-sync
dnf clean all
## virtual reboot
wsl -l -v
wsl -t CentOS
rm -f /var/lib/rpm/__db*
rpm --rebuilddb
dnf -y groupupdate "Core" "Minimal Install"
