Conditional Logic in PowerShell

http://www.powershellpro.com/powershell-tutorial-introduction/powershell-tutorial-conditional-logic/

Operator	Description
-eq	Equal to
-lt	Less than
-gt	Greater than
-ge	Greater than or Eqaul to
-le	Less than or equal to
-ne	Not equal to

perator	Description
-not	Not
!	Not
-and	And
-or	Or