Linux executes a specific task after the network is started

Linux runs A specific task after the network is started. In the traditional linux Startup Process, the dependency processing of Service Startup occurs. For example, service B must be started only after service A is started. in this way, service B usually requires a lot of tests when starting. upstart is A new startup mechanism based on events, so that after service A starts, it can send an event to trigger startup of Service B. for example, a service must be executed after the network is started. you can define the upstart file of this service to reference start on (net-device-up) exec/usr/sbin/bar. sh bar. sh will be started after the NIC is started