Where can I check ethernet port connected or not

[MeDMaN]

I have an USB HDD for my router. I use the scsi-stop.sh script. It does what it has to do, but when I reach my HDD (and the hdd spin up) some strange errors appear in systems log. I think because the router can't reach the hdd while it spin up. I want to write a script which check specific ethernet ports and when the port is active the script overwrite the scsi-stop.sh standard spindown periods.
(in short: when I use my computer, the hdd must spinning continously)

Thanks in advance

[ABATAPA]

I want to write a script which check specific ethernet ports

robocfg show


show the status of ports.
Still, you can use 'ping ip' to check - whether the computer is on.

[MeDMaN]

Thanks a lot