fix_missing_lastname.ps1

<#
.SYNOPSIS
Updates lists with "Contacts" in the name, replacing any empty "Last Name" fields
with the company name, to prepare for migration to SharePoint Online.

Syntax: fix_missing_lastname.ps1 -url "https://my.sharepoint.site" or update parameter below

.DESCRIPTION
Will scan one-level deep for sub-sites that have a list with 'Contacts' in the title. 	
.NOTES
	Author: Quinten Steenhuis
#>
param (
	[string]$url = "https://my.sharepoint.site"
)

Start-SPAssignment -Global
$parentWeb = get-spweb $url

$webs = $parentWeb.webs

foreach ($web in $webs) {
	$lists = $web.lists | Where title -like "*contacts*"
	foreach ($list in $lists) {
		$items = $list.items
		foreach ($item in $items) {
			if ($item["Last Name"] -like "") {
				if (-not ($item["Company"] -like "") ) {
					$item["Last Name"] = $item["Company"]
					$item.Update()
				} else if (-not ($item["First Name"] -like ""){
					$item["Last Name"] = $item["First Name"]
					$item.Update()
				}
			}
		}
	}
}
$ParentWeb.Dispose()
Stop-SPAssignment -Global