How to determine interface RUNNING state without ifconfig?

Some background: sometimes my wi-fi connection suddenly goes down so I type sudo ifconfig wlan0 and check for the word RUNNING. The corresponding line looks like: UP BROADCAST RUNNING MULTICAST [...] When the connection goes down there's no RUNNING setting; I can't connect to anything but the interface is still up. I'm thinking of writing a script to periodically check for the RUNNING state. To extract that string, using awk would be something like: sudo ifconfig wlan0 | awk '/RUNNING/ {print $3}'. Is there another way such as checking the filesystem instead of parsing ifconfig's output? I'm using Debian Wheezy. Thanks. --- **More information:** OK, just did some research and cleared up some conceptual confusion. The UP and RUNNING flags are different. The first means the interface "is currently initialized" , i.e. "the system allocated the resources for the interface" --it doesn't say anything about packet transmission. The RUNNING flag actually indicates that packets are being sent and received. Apparently this flag disappears if e.g. the ethernet cable is unplugged. https://docs.oracle.com/cd/E19253-01/816-4554/ipconfig-141/index.html https://stackoverflow.com/questions/11679514/what-is-the-difference-between-iff-up-and-iff-running I don't know what is going on with my (or any) wireless connection, but the result is the same: the interface remains up (the wi-fi led light remains on in my laptop) while the connection is completely lost.