Get Uptime for Linux and Windows machines in Azure

Get-AzSystemUptime

# Function - Get Azure Virtual Machine System Uptime
function Get-AzSystemUptime {
    param (
        [string] $subscriptionId,
        [string] $resourceGroup,
        [string] $vmName
    )

    if ($subscriptionId) {
        Set-AzContext -SubscriptionId $subscriptionId | Out-Null
        $subFriendlyName = (Get-AzContext).Subscription.Name
        Write-Output "[Azure] :: Setting Azure Subscription to $subFriendlyName "
    }

    $vmState = (Get-AzVM -ResourceGroupName $resourceGroup -Name $vmName -Status).Statuses.DisplayStatus[1]
    if ($vmState -ne 'VM running') {
        Write-Warning "[Azure] :: $vmName is not running. Please start the VM and try again."
        return
    }

    $osType = (Get-AzVM -ResourceGroupName $resourceGroup -Name $vmName).StorageProfile.OsDisk.OsType

    if ($osType -eq 'Windows') {
        Write-Output "[Azure] :: Getting System Uptime for $vmName in $resourceGroup..."
        Write-Warning "This may take up to 35 seconds"
        $response = Invoke-AzVMRunCommand -ResourceGroupName $resourceGroup -Name $vmName -CommandId 'RunPowerShellScript' -ScriptString '

        function ConvertToReadableTime {
            param (
                [int]$uptimeSeconds
            )
            $uptime = New-TimeSpan -Seconds $uptimeSeconds
            "{0} days, {1} hours, {2} minutes, {3} seconds" -f $uptime.Days, $uptime.Hours, $uptime.Minutes, $uptime.Seconds
        }

        # Get the hostname
        $hostname = [System.Net.Dns]::GetHostName()

        # Get the operating system information
        $operatingSystem = Get-CimInstance Win32_OperatingSystem

        # Get the uptime in seconds
        $uptimeSeconds = (Get-Date) - $operatingSystem.LastBootUpTime
        $uptimeSeconds = $uptimeSeconds.TotalSeconds

        # Convert uptime to a readable format
        $uptime = ConvertToReadableTime -uptimeSeconds $uptimeSeconds

        # Get the last reboot time
        $lastRebootTime = $operatingSystem.LastBootUpTime
        $lastRebootTime = $lastRebootTime.ToString("dd/MM/yyyy HH:mm:ss")

        # Display the results
        Write-Output " " # Required for script spacing
        Write-Output "[Azure] :: Hostname: $hostname"
        Write-Output "[Azure] :: Uptime: $uptime"
        Write-Output "[Azure] :: Last Reboot Time: $lastRebootTime"
        '

        $response.Value[0].Message
    }

    if ($osType -eq 'Linux') {
        Write-Output "[Azure] :: Getting System Uptime for $vmName in $resourceGroup..."
        Write-Warning "This may take up to 35 seconds"
        $response = Invoke-AzVMRunCommand -ResourceGroupName $resourceGroup -Name $vmName -CommandId 'RunShellScript' -ScriptString '
        echo "[Azure] :: Hostname: $(hostname)"
        echo "[Azure] :: Uptime: $(uptime -p )"
        echo "[Azure] :: Last Reboot Time: $(uptime -s)"
        '

        $pattern = '\[stdout\]([\s\S]*?)\[stderr\]'
        if ($response.value[0].Message -match $pattern) {
            $stdoutText = $matches[1].Trim()
            Write-Output `r $stdoutText
        }
    }
}