The equivalent, btw, is:

  ls | where length -gt 4kb

The only difference is powershell uses “>” and “<” for redirection, and so uses mnemonic operators for comparisons.

Nu doesn't seem to support redirection (or even have anything other than one input and one output stream, though metadata might serve the purposes otherwise served by additional streams; it's not how a program would return something Nu would treat as metadata, though.)

I guess that with a structured-data shell, error type of info could just be returned in-band under a different tag, in any case.