### WIFI DEVICE
$ cat /etc/hostname.iwx0
join DiskMate wpakey P455W0R7
join freifunk-rhein-neckar.de
join iPhone wpakey P455W0R7
up

### ETHERNET DEVICE
$ cat /etc/hostname.re0
up

### ADD THEM TO THE TRUNK
$ cat /etc/hostname.trunk0
trunkproto failover
trunkport re0
trunkport iwx0
inet autoconf
inet6 autoconf

# Now trunk0 is your virtual interface which uses
# ethernet when connected and wifi otherwise