The null device is a special file that discards all data written to it, but reports that the write operation succeeded.
Nul is often used to hide the output (or error output) of a command.
It is called NUL rather than NULL for historical reasons. It's not possible to create a file named "nul" on Windows.
Nul provides no data to any process that reads from it (yielding EOF immediately)
For more examples see the redirection page.
“Never mistake activity for achievement.” ~ John Wooden
PRN - redirect to the printer LPT1.
Equivalent PowerShell: $Null