Usage: nix-worker [OPTIONS...] [--daemon | --slave]

`nix-worker' is a helper program used to implement secure, multi-user
Nix stores.  In `--daemon' mode, it goes into the background and waits
for incoming connections on a Unix domain socket, and forks a process
for each connection to perform the Nix store operations requested by
the caller.  In `--slave' mode, `nix-worker' is called directly, and
the caller and the worker communicate with each other over
stdin/stdout.  In this mode, the `nix-worker' program should have
appropriate setuid privileges.