A script to find and connect to known wifi networks on OpenBSD. Works for me on my iwn card in my laptop

find_networks.sh

#!/bin/sh
# find_network.sh - An OpenBSD Wireless Network configurator
# Looks for available networks listed at the end of the script
# Use this by adding "!/path/to/find_network.sh \$if" to your wlan hostname.if
if=$1

if [ -z "$if" ]; then
	echo "Usage: $0 interface" >&2
	exit 2;
fi

# Annoyingly have to build the list of possible matches
# because otherwise we can't quote things properly
# Probably a better solution for this  . . .
dq='"\([^"]*\)"'
sq="'\([^']*\)'"
sp="\([^ ]*\)"

conf_match=''
for m in "$dq" "$sq" "$sp"; do
	conf_match="$conf_match /^$m.*/{s//\1/p;d;};"
done


TMP=`mktemp wifinwid-TMP-XXXXXX`
trap 'rm -f $TMP; exit 1' 0 1 2 15

# First reset the interface as that makes the scan more reliable
ifconfig $if -bssid -chan -nwid -nwkey -wpa -wpakey down

# Then actually perform the scan
ifconfig $if scan |
    sed -ne 's/^[[:space:]]*nwid \(.*\) chan .*$/\1/p' |
    while read line ; do
	if [ "${line% *}" != "$line" ]; then
		line=${line%\"}
		line=${line#\"}
	fi
	echo $line
    done | sort -u > $TMP

if [ ! -s $TMP ]; then
	echo "No networks found"
	exit 3
fi

while read conf; do
	[ -z "$conf" ] && continue                  # skip empty
	[ X"${conf#\#}" == X"${conf}" ] || continue # skip comments

	nwid=`echo "$conf" | sed -ne "$conf_match"`
	if grep -q "^$nwid$" $TMP; then
		# need to eval for possible quotes in $conf
		echo "Connecting to $nwid"
		eval ifconfig $if nwid $conf up
		break
	fi
done <<EOL
# List your nwid's plus any options here, including quotes if necessary
# This list is in order of preference, it looks for these networks in order.
# This could easily become an external file
"#SFO FREE WIFI" chan 44
myHouse nwkey "MyKey"
linksys
EOL

reconnect_network.sh

#!/bin/sh
if=$1

# I put this into my /etc/hostname.$if file:
# !/usr/local/bin/reconnect_network \$if &
# dhcp

if pgrep -f "$( basename $0 ).*$if" | grep -q -v ^$$\$; then
    echo "Already running on $if"
    exit 2
fi

ifconfig $if up

while true; do
    if ifconfig $if | grep -q 'status: active'; then
      sleep 5
    elif ifconfig $if | head -1 | grep -q -v UP; then
      echo exiting
      exit
    else
      $(dirname $0)/find_network.sh $if
      sleep 30
    fi
done