Syntaxt of selection is located at
https://pkg.go.dev/github.com/ipld/go-ipld-selector-text-lite#SelectorSpecFromPath
Example use, assuming that:
- The root of the deal is a plain dag-pb unixfs directory
- The directory is not sharded
- The user wants to retrieve the first entry in that directory
lotus client retrieve --miner f0XXXXX --datamodel-path-selector 'Links/0/Hash' bafyROOTCID ~/output
For a much more elaborate example see the top of ./itests/deals_partial_retrieval_test.go
