Socket activation for systemd services. More information: https://www.freedesktop.org/software/systemd/man/latest/systemd-socket-activate.html.
systemd-socket-activate path/to/socket.service
systemd-socket-activate path/to/socket1.service path/to/socket2.service
SYSTEMD_SOCKET_ACTIVATION=1 systemd-socket-activate path/to/socket.service
systemd-socket-activate path/to/socket.socket path/to/service.service
systemd-socket-activate path/to/socket.service -l 8080