a script to generate and show a QR-code containing the SSID and passphrase for the currently-connected WiFi network

show_wifi_qr.sh

#!/usr/bin/env bash

# a script to generate and show a QR-code containing the SSID and passphrase
# for the currently-connected WiFi network, for systems using NetworkManager

# the network device
DEVICE=wlp0s20f3

# need root to get password
if [ "$EUID" -ne 0 ]
  then echo "This script must be run as root"
  exit
fi

# get the currently connected network SSID
SSID=$(iw ${DEVICE} info | grep -Po '(?<=ssid ).*')

# the networkmanager config file that stores security info
NMPATH=/etc/NetworkManager/system-connections/${SSID}.nmconnection

# check if this network is secured
SEC=$(grep "wifi-security" ${NMPATH})

# if this network has no wifi-security, there is no password!
if [ -z "$SEC" ]; then
  echo "Connected network \"${SSID}\" has no password!"
  exit
fi

SEC=$(grep "wpa-psk" ${NMPATH})

# currently set up for wpa-psk only (doing WPA2 would be trivial too)
if [ -z "$SEC" ]; then
  echo "Connected network \"${SSID}\" is not WPA-PSK security"
  exit
fi

SSID_PASS=$(sudo cat ${NMPATH} | grep -Po '(?<=psk=).*')

qrencode -t UTF8 "WIFI:S:${SSID};T:WPA;P:${SSID_PASS};;"