<#
.SYNOPSIS
	upgrade-ubuntu.ps1 
.DESCRIPTION
	Upgrades Ubuntu Linux to the latest (LTS) release.
.EXAMPLE
	PS> .\upgrade-ubuntu.ps1 
.NOTES
	Author: Markus Fleschutz · License: CC0
.LINK
	https://github.com/fleschutz/PowerShell
#>

try {
	""
	"Step 1/4: Perform a Backup"
	"--------------------------"
	"It's strongly recommended to perform a backup of your data BEFORE upgrading the OS!"
	$Confirm = read-host "Press <Return> to continue..."

	""
	"Step 2/4: Install update-manager-core, Upgrade Packages & Reboot"
	"----------------------------------------------------------------"
	$Confirm = read-host "Enter <yes> to perform this step (otherwise this step will be skipped)"
	if ($Confirm -eq "yes") {
		sudo apt install update-manager-core
		sudo apt update
		sudo apt list --upgradable
		sudo apt upgrade
		sudo reboot 
	}

	""
	"Step 3/4: Remove obsolete Kernel Modules"
	"----------------------------------------"
	$Confirm = read-host "Enter <yes> to perform this step (otherwise this step will be skipped)"
	if ($Confirm -eq "yes") {
		sudo apt --purge autoremove
	}

	""
	"Step 4/4: Upgrade Ubuntu & Reboot"
	"---------------------------------"
	$Confirm = read-host "Enter <yes> to perform this step (otherwise this step will be skipped)"
	if ($Confirm -eq "yes") {
		sudo do-release-upgrade # to latest LTS version
		#sudo do-release-upgrade -d # to latest supported release
		sudo reboot
	}

	"✔️  Done."
	exit 0
} catch {
	write-error "⚠️ Error in line $($_.InvocationInfo.ScriptLineNumber): $($Error[0])"
	exit 1
}