These include the large middle-class suburbs of Peoria, Mesa, Chandler, and Glendale; upscale Scottsdale; and the college area of Tempe which serves as home to Arizona State University. All areas are modern and generally lacking in historic interest, but keep in mind that Phoenix only had 100,000 residents in 1950.
do {} until ($false) is an infinite loop; it'll only exit if you use something like break, return or throw from inside the loop body. do { } until ($true) would execute the loop body exactly once (which would make the loop rather pointless.) It looks like what you intended to do was wait for a file to exist.
It's a PowerShell equivalent to opening a file with Notepad, doing a find-and-replace operation, and saving the file. But unlike Notepad, you can use this script to replace strings in multiple files at the same time. Replace-FileString.ps1 supports searching across line breaks because it uses the ReadAllText method of the Windows .NET Framework's System.IO.File class instead of the Get-Content cmdlet to read in text.