[Unix] -r [Description] Use this file as a reference instead of the current time. [PowerShell] 
-reference
- f i l e s p e c
- d a t e t i m e
- f o r w a r d
- r e f e r e n c e
- o n l y _ m o d i f i c a t i o n
- o n l y _ a c c e s s