The script is available for download from https://gallery.technet.microsoft.com//How-to-add-startup-1b03e3dd. You can also use Microsoft Script Browser for Windows PowerShell ISE to download the sample with one button click from within your scripting environment.
This PowerShell script show how to add startup parameters for all the SQL Server instances.
Some people ask how to add startup parameters to a batch of SQL Server instances. If we add the parameters one by one for all the instances on a SQL Server, it will cost a lot of time. This script will help you achieve your goal in a convenient way. If the startup parameters already exist on the server, the script will skip the ones.
You can find more All-In-One Script Framework script samples at https://aka.ms/onescriptingallery