README for aircrack-ng
POST-INSTALL
1. The airmon-ng tool included in aircrack-ng requires 'iw' to be installed.
Otherwise they will just abort with an error saying:
ERROR: Neither the sysfs interface links nor the iw command is available.
Please download and install iw from http://dl.aircrack-ng.org/iw.tar.bz2
So, you can safely install 'iw' from contrib ports by doing:
# ports -u contrib; prt-get install iw