function Replace-String($find, $replace, $path)
{
	echo "Replacing string `"$find`" with string `"$replace`" in file contents and file names of path: $path"
    ls $path | select-string $find -list |% { echo "Processing contents of $($_.Path)"; (get-content $_.Path) |% { $_ -replace $find, $replace } | set-content $_.Path -Force }
	ls $path\*$find* |% { echo "Renaming $($_.FullName) to $($_.FullName.Replace($find, $replace))";mv $_.FullName $_.FullName.Replace($find, $replace) }
}

# Example
Replace-String "Temp1" "Temp2" "D:\Temp"

Replace String in file contents and file names using PowerShell

Windows PowerShell