iwconfig - getting rid of the useless stuff in the output

[starsky512]

iwconfig displays all of my network interfaces, not just the ones with wireless extensions. I wouldn't mind that, if it was actually possible to grep out the right, wireless one.

An example:

$ iwconfig | grep ESSID | cut -f 1 -d ' '
lo        no wireless extensions.

eth0      no wireless extensions.

wmaster0  no wireless extensions.

pan0      no wireless extensions.

eth1

As you can see, the right name (eth1) is displayed, but along with it iwconfig echoes a bunch of useless stuff.

How can I get rid of it?

I've found out that saving the grepped iwconfig output to a variable does actually work, but the script still echoes the non-wireless interfaces, for instance:

$ interface=$(iwconfig | grep ESSID | cut -f 1 -d ' ')
lo        no wireless extensions.

eth0      no wireless extensions.

wmaster0  no wireless extensions.

pan0      no wireless extensions.

$ echo $interface
eth1

How can I prevent it from doing so?

Thanks.

[Rubberman]

What does this have to do with programming and scripts? Please move this thread to the wireless forum for appropriate help.