Get-Uptime.psm1

function Get-Uptime {
	<#

	.SYNOPSIS
	Gets the uptime of computers.

	.DESCRIPTION
	Gets the uptime of computers.

	.EXAMPLE
	Get-Uptime -ComputerName "computer01","computer02" | Sort-Object -Descending "TotalSeconds" | Format-Table "PSComputerName","PrettyString"

	#>

	[CmdletBinding()]
	Param(
		[Parameter(Mandatory=$false)] [string[]] $ComputerName = $null
	)

	Begin {
		Set-StrictMode -Version "Latest"
		Set-Variable -Name "ErrorActionPreference" -Scope "Script" -Value "Stop"

		[HashTable] $Arguments = @{}

		# Done to prevent calling localhost if no computers is given. The calling user might have the right to call WMI, but not Invoke-Command on localhost.
		if ($ComputerName -ne $null) {
			$Arguments = @{"ComputerName" = $ComputerName}
		}
	}

	Process {
		Invoke-Command @Arguments -ScriptBlock {
			$WMI = Get-WmiObject -Class Win32_OperatingSystem
			$TimeSpan = $WMI.ConvertToDateTime($WMI.LocalDateTime) – $WMI.ConvertToDateTime($WMI.LastBootUpTime)

			$PrettyString = ""

			if ($TimeSpan.TotalDays -gt 0) {
				$PrettyString += "$($TimeSpan.Days) days, "
			}
			if ($TimeSpan.TotalHours -gt 0) {
				$PrettyString += "$($TimeSpan.Hours) hours, "
			}
			if ($TimeSpan.TotalMinutes -gt 0) {
				$PrettyString += "$($TimeSpan.Minutes) minutes, "
			}
			if ($TimeSpan.TotalSeconds -gt 0) {
				$PrettyString += "$($TimeSpan.Seconds) seconds, "
			}
			if ($TimeSpan.TotalMilliseconds -gt 0) {
				$PrettyString += "$($TimeSpan.Milliseconds) milliseconds"
			}

			$TimeSpan | Add-Member -MemberType "NoteProperty" -Name "PrettyString" -Value $PrettyString

			return $TimeSpan
		}
	}
}