I see that, like ed(1), stockfish is generous enough to flag errors, yet prudent enough not to overwhelm the novice with verbosity. $ ./stockfish_14_x64_bmi2 Stockfish 14 by the Stockfish developers (see AUTHORS file) help Unknown command: help ? Unknown command: ? eat flaming death Unknown command: eat flaming death
Here's an immediately usable browser version (supports WebAssembly with SIMD instructions):
If you want to experiment with ./stockfish anyway, the protocol documentation is here:
https://www.shredderchess.com/chess-features/uci-universal-c...
edit: also someone mirrored it here (in a more convenient format)
https://gist.github.com/DOBRO/2592c6dad754ba67e6dcaec8c90165...