How to Write Files to /dev/null in Powershell and CMD on Windows?

Question

In CMD.exe I can copy files to /dev/null/ like this: copy foo.bar NUL

But when type: rar.exe x fileToBeExtracted.rar NUL It will throw a error.

In Powershell I can Not copy files to /dev/null/ like CMD: copy foo.bar NUL or Copy-Item foo.bar NUL or rar.exe x fileToBeExtracted.rar NUL

What can I do to make all above work ?