MARCedit has a CLI:
https://marcedit.reeset.net/cmarcedit-exe-using-the-command-line

Looks like the `-xmltomarc` flag is what you want, though I've not used it
for this purpose myself.

Best,
Eric


On Tue, Aug 8, 2023 at 11:57 AM Eric Lease Morgan <
[log in to unmask]> wrote:

> I have a 500MB MARCXML file, and I want to create a corresponding MARC
> file in communications format -- "standard" MARC. What command-line
> utilities can do this sort of work? --Eric Morgan
>