Re: find clips that are not used by projects or productions

[Mark Davidson] "On the command line, I can run ./fcsvr_client list_parent_links /asset/25123 and it will show me the productions that use that movie asset."

No.
./fcsvr_client list_parent_links /asset/XXXX
...will show you the Original Media (Primary Representation), Proxies, Thumbnails, Poster Frames, and Elements.

If you want to see the Productions an asset is a member of, do:
./fcsvr_client list_child_links /asset/XXXX
The listings for /project/XXXX represent Productions, not FCP Projects.
To track down the FCP projects that link to an Asset, get your output from:
./fcsvr_client list_parent_links /asset/XXXX
...to get the /element/XXXX values.

Then for each /element/XXXX value, run:
./fcsvr_client list_child_links /element/XXXX
The output will include a "Member(1): /asset/XXXXX" listing that corresponds to the FCP project that links to your original asset. Each /element/XXXX listing from the list_parent_links on your initial Asset will trace to a different FCP project.

Best,
Andy