Can PowerShell script out SQL Server Reporting Services RDL files?

a little late, but here you go

This PowerShell script : 1. Connects to your report server 2. Creates the same folder structure you have in your Report Server 3. Download all the SSRS Report Definition (RDL) files into their respective folders

https://sqlbelle.wordpress.com/2011/03/28/how-to-download-all-your-ssrs-report-definitions-rdl-files-using-powershell/

PowerShell doesn't provide any native, PowerShell-esque functionality for this, no. You can do this in PowerShell (as noted in the previous answer) only because PowerShell can access the underlying Framework classes. As you noted in your comment to the previous answer, it's no different from using the API in C# or VB.

The SQL Server team has not yet provided much in the way of PowerShell-specific stuff. They're primarily relying on .NET and T-SQL as "scripting languages."

I just realized the Content column in the ReportServer.dbo.Catalog contains the definition in an Image format. I wrote the following code to convert it to readable text:

SELECT CONVERT(VARCHAR(MAX), CONVERT(NVARCHAR(MAX), CONVERT(XML, CONVERT(VARBINARY(MAX), Content))))
FROM [ReportServer].[dbo].[Catalog]
WHERE Type = 2

With the above code, I can now automate writing the results to a flat file and then import the file into my version control system.