how to identify interface down time

[mina.moussa]

guys is there a way to identify how long an switchport interface has been down?

we trying to identify the interfaces that are cabled up but have not been in use for a while at a remote site.

[Leo Laohoo]

The command is "sh interface".   Look for the line "Last input".

[mina.moussa]

I'm not sure how reliable that is, what causes those stats to be reset other then the obvious stat reset command.

[Leo Laohoo]

 I'm not sure how reliable that is

Very reliable.

what causes those stats to be reset other then the obvious stat reset command.

The reset command will NOT zero this particular counter.  It's a "live" counter.