WMI, GetEnumerator Sort HashTable. the where {$_} is one way to ensure that there is data on that line of the text file when you read it in. The GetEnumertor method enumerates through each item in the hash table to allow a sort of the objects. See about_hash_tables for more info. Note that a hashtable has a key and a value property which you can access. You are expanding the value to be able to perform actions (in this case checking the free memory.