конфигурация сервисного блока (Service unit configuration)
SERVICE TEMPLATES
It is possible for systemd services to take a single argument via
the "service@argument.service" syntax. Such services are called
"instantiated" services, while the unit definition without the
argument parameter is called a "template". An example could be a
dhcpcd@.service service template which takes a network interface
as a parameter to form an instantiated service. Within the
service file, this parameter or "instance name" can be accessed
with %-specifiers. See systemd.unit(5) for details.
