Make a SharePoint site searchable or not searchable

Here are the steps to make a SharePoint site searchable in general:

https://support.office.com/en-us/article/Enable-content-to-be-searchable-d7ba92db-8618-43fe-87ee-adf03d973062

A simple PowerShell script that makes a SharePoint site not searchable:

https://sharepoint.stackexchange.com/questions/36717/powershell-or-script-to-make-all-lists-and-libraries-unsearchable

and a more complete PowerShell script:

https://gallery.technet.microsoft.com/office/How-to-configure-a-6820f0d5