function Get-TimeStamp {

    return "[{0:MM/dd/yy} {0:HH:mm:ss}]" -f (Get-Date)

}

# Set this to the path to your Steam install
$SteamPath = "C:\Program Files (x86)\Steam\"
# Set this to your Steam ID number
$SteamID = "xxxxxxx"

#Build the path to the MHW userdata folder
$SaveFile = $SteamPath + "userdata\" + $SteamID + "\582010\remote\SAVEDATA1000"

#Path you wish to backup to.  By default to the root of your SteamID folder in Steam's Userdata folder.
$BackupPath = $SteamPath + "userdata\" + $SteamID + "\MHWBackup"
$LogFile = $BackupPath + "\BackupLog.log"
$LastFileHash = $BackupPath + "\LastSaveHash.txt"

$SHA256 = Get-FileHash -Path $SaveFile
if(Test-Path $LastFileHash) {
    $LastBackupHash = Get-Content $LastFileHash
}
else {
    $LastBackupHash = ""
}

Write-Output "$(Get-TimeStamp) Hash of current save is $($SHA256.Hash)" | Out-File -FilePath $Logfile -Append

if ($SHA256.Hash -ne $LastBackupHash) {
    Write-Output "$(Get-TimeStamp) hash of last save is $LastBackupHash.  Performing backup of new save file." | Out-File -FilePath $LogFile -Append
    $Timestamp = Get-Date -Format "yyyyMMdd_HHmmss-"
    #Compress a copy of the current save file to the backup path
    Compress-Archive -Path $SaveFile -Destinationpath ($BackupPath + "\" + $TimeStamp + "Backup.zip") -CompressionLevel Optimal
    Write-Output "$(Get-TimeStamp) Backed up to $BackupPath\$TimeStamp`Backup.zip" | Out-File -FilePath $Logfile -Append
    #Update the LastFileHash
    $SHA256.Hash | Out-File -FilePath $LastFileHash -Force
}
else {
    Write-Output "$(Get-TimeStamp) Hash of last save is $LastBackupHash.  No changes to save file, no backup needed." | Out-File -FilePath $Logfile -Append
}

Write-Output "$(Get-TimeStamp) Backup process complete." | Out-File -FilePath $Logfile -Append