Question : Determining if something exists in Powershell

This is going to be kind of a weird one to explain.
I'm trying to write a code that will go through an AD Domain and build Security Groups for each OU, placing them in a specific, separate OU. I have the code for this already, it works great, but I want to add a little more functionality.

What I'm wondering is, what would I do in an if statement to determine if a security group exists or if a user is already a member of a group, etc. etc. etc.

Basically, if I wanted to write a script that looked through an OU for users, and checked to see if they were already a member of a specific security group, what would that look like?

Answer : Determining if something exists in Powershell

This is somewhat related.
If you have Excel set up to start a new process for each Sheet, it will do what is happening with your XP machine.
Be default, the behaviour is per the Vista/7 machines.

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