Detecting a change of IP address in Linux

Question

Does anyone know a way to detect a change of IP address in Linux. Say I have dhcpcd running, and it assigns a new IP address, is there a way I can get a notification when it

Answer 1

The command

ip monitor

will show you this kind of thing happening. It uses some the netlink API which is rather tricky and not documented well (at least for humans to understand). However, it is able to get notified by the kernel of various events, such as changes of assigned IPs, routing tables and link status (e.g. someone unplugged the network)