Lex/Yacc for C#?

Still early CTP so can't be used in production apps but you may be interested in Oslo/MGrammar: http://msdn.microsoft.com/en-us/oslo/

Also look at Antlr, which has C# support.

I've done a couple of small projects with GPLEX/GPPG, which are pretty straightforward reimplementations of LEX/YACC in C#. I've not used any of the other tools above, so I can't really compare them, but these worked fine.

GPPG can be found here and GPLEX here.

That being said, I agree, a full LEX/YACC solution probably is overkill for your problem. I would suggest generating a set of bindings using IronPython: it interfaces easily with .NET code, non-programmers seem to find the basic syntax fairly usable, and it gives you a lot of flexibility/power if you choose to use it.

I'm not sure Lex/Yacc will be of any help. You'll just need a basic tokenizer and an interpreter which are faster to write by hand. If you're still into parsing route see Irony.

As a sidenote: have you considered PowerShell and its commandlets?