netreport - Unix, Linux Command
netreport - request notification of network interface changes
tells the network management scripts to send a SIGIO signal
to the process which called netreport when any network interface
status changes occur.
Remove the current request (if any) for the calling process.
If a program does not call netreport with the
option before it exits, and another process is created with the
same PID before any changes take place in interface status, it
is possible that the new process will receive a spurious SIGIO.