Never Modify PowerShell's XML Files

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MSDN Blog Postings » 2008 » March » 21 — Sat, 22 Mar 2008 04:54:43 GMT

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re: Never Modify PowerShell's XML Files

anonymous — Sat, 22 Mar 2008 05:00:52 GMT

I think it's safer to pluralize as PMs.

re: Never Modify PowerShell's XML Files

Eric Travers — Sat, 22 Mar 2008 16:32:26 GMT

I have a situation were I have two machines that will not allow me to uninstall version 1.0 to upgrade to ver. 2.

What is the recommended course of action in this instance? Should I manually scrub version 1?

re: Never Modify PowerShell's XML Files

Marty — Sat, 22 Mar 2008 16:54:14 GMT

I think this is the correct decision to ensure stabile/predictable PowerShell installs, but it makes me wonder why you use XML in the first place. XML is inefficient and full of fluff, but the biggest advantage is the standards-based human-readable format, so using XML is almost encouraging people to make changes. It's quite common for software vendors would intentionally save things in a proprietry format so people would not be tempted to make changes, and if they did you could say well you shouldn't be hacking our files. So I'm OK with the outcome of the meeting (pave and roll - LOL), I've made some custom formatting in my own files. But if this wasn't XML (or it was compressed/encoded) and you provided some XML formatting examples, you probably wouldn't have needed to have a painful and ugly meeting in the first place.

re: Never Modify PowerShell's XML Files

Don Jones — Sat, 22 Mar 2008 20:46:15 GMT

The included XML files are signed using an MS signature; modifying them breaks that signature. If you're running a secure ExecutionPolicy (AllSigned), a broken signature prevents the files from loading unless you re-sign it. So it makes a LOT more sense to just make your own files (www.sapienpress.com/powershell2.asp includes chapters on doing so) and load them in your profile - better security along with the described convenience when installing updates.

re: Never Modify PowerShell's XML Files

Marty — Sun, 23 Mar 2008 17:29:08 GMT

I just checked the XML files in C:\Windows\System32\WindowsPowerShell\v1.0\ and I don't see any signatures.

re: Never Modify PowerShell's XML Files

Chris — Mon, 24 Mar 2008 08:10:56 GMT

You might consider at least backing up the files if they differ from what's expected. Any Linux package management system would do this. No reason to to be so hard about it.