Scripting Games January 2016: Get-PCBUptime

sg-2016-01.ps1

function Get-PCBUptime {
<#
.SYNOPSIS
A simple tool for checking how long a system on the network has been running since last boot.
.DESCRIPTION
Get-PCBUptime is a quick WMI-based tool for determinging a remote system's uptime.  It is useful for verifying
what a user says when asked if they've rebooted their machine recently, or to generate a report of server uptimes.

Get-PCBUptime is written by and copyright of Christopher R. Lowery, aka The PowerShell Bear (poshcodebear.com; Twitter: @poshcodebear)
It is free for all to use, and free to distribute with attribution to the original author.

This is a special version modified specifically for the Scripting Games.
.PARAMETER ComputerName
The name of the Computer to check; if left blank, it defaults to "localhost".
.EXAMPLE
Get-PCBUptime -ComputerName system
.LINK
http://www.poshcodebear.com
#>
    [CmdletBinding()]
    param(        
        [Parameter(ValueFromPipeline=$true)]
        [Alias('Host')]
        [string[]]$ComputerName = 'localhost'
    )
    BEGIN { }

    PROCESS {
        foreach ($Computer in $ComputerName) {
            if (Test-Connection -ComputerName $Computer -Quiet -Count 1) {
                try {
                    # Query remote machine
                    $os = Get-WmiObject -Class Win32_OperatingSystem -ComputerName $Computer -ErrorAction Stop
                    
                    # Calculate start time and uptime (rounded to 1/10th of a day)
                    $StartTime  = $os.ConvertToDateTime($os.LastBootUpTime)
                    $DaysUptime = [Math]::Round((((Get-Date) - $StartTime).TotalDays), 1)
                    $Status     = 'OK'
                    
                    # Determine if it might need to be patched
                    if ($DaysUptime -gt 30) { $PatchCheck = $true }
                    else                    { $PatchCheck = $false }
                }
                catch {
                    # There was a problem during the WMI query; set up different output and pass through the error
                    $StartTime  = 'Unknown'
                    $DaysUptime = 0
                    
                    $Status     = 'ERROR'
                    $PatchCheck = $false
                    
                    Write-Error $_
                }
                
                # Format output
                $props = [ordered]@{
                    'ComputerName'     = $Computer;
                    'StartTime'        = $StartTime;
                    'Uptime(Days)'     = $DaysUptime;
                    'Status'           = $Status;
                    'MightNeedPatched' = $PatchCheck;
                }
            }
            else {
                # Ping failed; throw warning and format output accordingly
                Write-Warning -Message "Computer $($Computer) does not respond to ping and may be offline"
                $props = [ordered]@{
                    'ComputerName'     = $Computer;
                    'StartTime'        = $null;
                    'Uptime(Days)'     = 0;
                    'Status'           = 'OFFLINE';
                    'MightNeedPatched' = $false;
                }
            }
            
            # Generate the output object with type
            $obj = New-Object -TypeName PSObject -Property $props
            $obj.PSObject.TypeNames.Insert(0,'PoshCodeBear.System.UpTime')
            Write-Output -InputObject $obj
        }
    }
    
    END { }
}