Commands are not distinguished from options except for the fact that only one command is allowed.
stdin. The default mode is to create a socket and listen for commands there.
--daemon [command line
As an alternative you may create a new process as a child of
gpg-agent --daemon /bin/sh. This way you get a new
shell with the environment setup properly; after you exit from this
shell, gpg-agent terminates within a few seconds.
In –supervised mode, different file descriptors can be provided for
use as different socket types (e.g. ssh, extra) as long as they are
identified in the environment variable
sd_listen_fds(3) on some Linux distributions for more information on