wi-fi_bash

#!/bin/bash

#set -o nounset
#set -o errexit
rm .list.tmp 2>/dev/null

if [[ "$1" == "down" ]]; then
    pkill wpa_supplicant
    ifconfig wlan0 down
    exit
fi
if [[ "$1" == "reload" ]]; then
    ifconfig wlan0 down
    pkill wpa_supplicant
    ifconfig wlan0 up
    wpa_supplicant -B -Dwext -i wlan0 -c /etc/wpa_supplicant/wpa_supplicant.conf && dhclient wlan0
    exit
fi

ifconfig wlan0 down
pkill wpa_supplicant
ifconfig wlan0 up

iface="wlan0"
iwlist $iface scan 2>/dev/null > .list.tmp
eval list=( $(cat .list.tmp | awk -F":" '/ESSID/{print $2}' | nl -w2 -n rz -s "=") )
#sets prompt
PS3="Choose wifi connection: "
#tests for number of wifi connections, exits if none
if [[ -z "${list[0]}" ]]; then
    clear
    echo "No available wifi connection"
    exit 1
fi
#menu of wifi connections
select item in "${list[@]}"; do
    #sets essid as value for WIFI variable and displays information about the AP
    cell=$(echo $item | awk -F"=" '{print $1}')
    essid=$(echo $item | awk -F"=" '{print $2}')
    sed -ni "/Cell $cell/,/Cell/ p" .list.tmp
    # delete spaces
    echo "$(cat .list.tmp | sed -n 's/^[ \t]*//')"
    #sets channel as value for CHANNEL variable
    channel=$(grep Channel: .list.tmp | sed 's/.*Channel://g')
    #sets pairwise chiphers
    pairwise=$(grep -m 1 Pairwise .list.tmp | sed 's/.* : //g')
    #sets group chiphers
    group=$(grep -m 1 Group .list.tmp | sed 's/.* : //g')
    #test for mode, if mode = master, sets MODE variable to managed
    mode=$(grep Mode .list.tmp | sed 's/.*Mode://g')
    if [[ "$mode" == "Master" ]]; then
        mode="managed"
    else
        clear
        echo "Cannot connect"
        exit
    fi
    #tests for encryption key
    key=$(grep key: .list.tmp | sed 's/.*key://g')
    if [[ $key == "on" ]]; then
        echo -n "Enter encryption key: "
        read key
    fi
    skey=$(wpa_passphrase "$essid" $key 2>/dev/null | sed -n 's/^[ \t]psk=//gp')
    #checks encryption algorithm
    IE=$(grep WPA .list.tmp | sed 's/.*: //g')
    if [[ -n "$IE" ]]; then
        echo "ctrl_interface=/var/run/wpa_supplicant
ap_scan=1
network={
ssid=\"$essid\"
scan_ssid=0
proto=WPA RSN
key_mgmt=WPA-PSK
pairwise=$pairwise
group=$group
psk=$skey
}" > /etc/wpa_supplicant/wpa_supplicant.conf
        rm .list.tmp 2>/dev/null
        wpa_supplicant -B -Dwext -i $iface -c /etc/wpa_supplicant/wpa_supplicant.conf && dhclient wlan0
        exit
    else
        #sets the wireless configuration for non WPA: essid, channel, mode, key, etc
        iwconfig $iface essid \""$essid"\" channel $channel mode $mode key $key
        #connects to wifi connection
        dhclient $iface
        exit
    fi
done