rlimit tweaking was removed in #3512. But without it, the rlimit is only 256, and I can't use hugo serve to preview even a relatively modest site without seeing this error:

Error: listen tcp 127.0.0.1:1313: socket: too many open files

The ulimit command still works fine for me in Sierra (10.12.6 beta), so I don't understand why it was removed from Hugo:

ulimit -n 10000; hugo serve

Any clarification on this, @bep?