wifi_scan.sh

#!/bin/bash

OUT_FILE="wifi_testing_$(date '+%Y-%m-%d_%H-%M-%S').pcap"
DWELL_TIME="1"

set -e

echo "[*] Enumerating devices"

readarray -t devices < <(iw dev | grep 'Interface' | awk '{print $2}' | sort)
num_devices=${#devices[@]}

if [ $num_devices -eq 0 ]; then
    echo "[!] No devices detected"
    exit 1
elif [ $num_devices -eq 1 ]; then
    device="${devices[0]}"
else
    echo "[!] More than one device detected"
    echo "[*] Select the device you want to use"
    echo

    echo "Devices:"
    for (( i=0; i<$num_devices; i++)); do
        echo "$((i+1)). ${devices[$i]}"
    done
    echo

    while true; do
        read -p "Device number: " dev_num
        if [ $dev_num -gt 0 ] && [ $dev_num -le $num_devices ]; then
            break
        fi
        echo "Invalid input"
    done

    device="${devices[$((dev_num-1))]}"
fi

echo "[*] Using $device. Getting config"

phy_num=$(iw dev wlan0 info | grep wiphy | awk '{print $2}')
phy="phy${phy_num}"
readarray -t channels < <(iw phy "$phy" channels | grep '*' | grep -v 'disabled' | awk -F'[' '{print $2}' | tr -d ']')

# This shouldn't actually be needed

echo "[!] Disabling system services. you won't have internet!"
sudo systemctl stop NetworkManager
sudo systemctl stop wpa_supplicant

echo "[*] Enabling monitor mode"
sudo ip link set "$device" down
sudo iw dev "$device" set type monitor
sudo ip link set "$device" up

echo "[*] Starting scanning"

tshark -w "$OUT_FILE" -i "$device" &>/dev/null &

for channel in ${channels[@]}; do
    echo "[*] Scanning channel $channel"
    sudo iw dev "$device" set channel "$channel"
    sleep "$DWELL_TIME"
done

kill %1

echo "[*] Done! Check $OUT_FILE"

sudo ip link set "$device" down
sudo iw dev "$device" set type managed
sudo ip link set "$device" up

sudo systemctl start NetworkManager
sudo systemctl start wpa_supplicant