Rename Files / Find and Replace File Names in SharePoint Document Library with PowerShell

#Get the Web  
$Web = Get-SPWeb "https://sharepoint.crescent.com"

#Get the List
$List = $Web.Lists["Design Documents"]

#Iterate Through All List Items
foreach($ListItem in $List.Items)
{
	if($null -ne $ListItem.File) #Exclude Document Sets
	{
		Write-Host "Checking $($ListItem.Name)..."
		#Check out, if Require checkout is enabled
		#$ListItem.File.CheckOut()
		#Replace "Crescent" with "Crescent Inc."
		$ListItem["Name"] = $ListItem["Name"].replace("Crescent","Crescent Inc.")
		#Update the changes
		$ListItem.Update()
		#$ListItem.File.CheckIn("Updated the File Name")
	}
}