PoliMi Protected shell connection script

#!/bin/sh
## polimi-protected sh handler
## Made by Giovanni Santini (ItachiSan @ github.com)
# --------------------------------------------------------------------
# connects to 'polimi-protected' wifi AP on ArchLinux
# This works for ArchLinux, for else you may need to edit this script
# --------------------------------------------------------------------
# You should have:
# systemctl -> daemon manager (in this case, his power is OVAH 9000)
# ifconfig/iwconfig/wpa_supplicant/dhclient -> quite common net tools
# polimi-protected.conf/ca.pem/wifiCert.p12 -> polimi connection stuff (I suppose you're a PoliMi student)
# --------------------------------------------------------------------
# Edit this script at your wish but give proper credits ;)

## Declaration Time
# Your device iface (you can find it with ifconfig)
DEV=wlp2s0
# wpa_supplicant driver (wext should work fine for everyone)
DRIVER=wext
# root part; if not ran as root, we use sudo
SU=sudo
if [ "$(id -u)" = "0" ]; then
   SU=''
fi
#
SERVICE_STOP='systemctl stop'
#EOF Declarations

# The real program
case $1 in
sh)
    # Killing services (about 30 times, so we're sure they're dead)
    for ((i = 1; i <= 30; i++)); do
        $SU $SERVICE_STOP NetworkManager-wait-online.service
        $SU $SERVICE_STOP NetworkManager.service
        $SU $SERVICE_STOP wpa_supplicant.service
        killall wpa_supplicant 2&>/dev/null
    done

    #Setting up all the stuff
    echo 'Configuring stuff with net toools...'
    $SU ifconfig $DEV down
    $SU ifconfig $DEV up
    $SU iwconfig $DEV essid polimi-protected
    $SU wpa_supplicant -i $DEV -D $DRIVER -c polimi-protected.conf -d
    echo 'Sleeping for a while...'
    sleep 15
    $SU dhclient $DEV
    echo 'Done!'
    exit 0
    ;;
*)
    echo 'Need an input (usually "sh")'
    exit 0
    ;;
esac