Adjust my Powershell-Script to use a Dictionary

My script : $configFiles = Get-ChildItem . *.config -rec foreach ($file in $configFiles) { (Get-Content $[login to view URL]) | Foreach-Object { $_ -replace "Dev", "Demo" } | Set-Content $[login to view URL] } What i want to accomplish : Replace "Dev" with a random string from $[login to view URL]