tunnelbroker.net automatic tunnel IP update and tunnel setup (on Linux)

tunnelbroker-net.sh

#!/bin/bash

# This script is published by Philipp Klaus <philipp.l.klaus@web.de>
# on <http://blog.philippklaus.de/2011/05/ipv6-6in4-tunnel-via-hurricane-electric-tunnelbroker-net-automatic-ip-update-on-mac-os-x/>
# It is originally by freese60 and modified by limemonkey.
# Found on <http://www.tunnelbroker.net/forums/index.php?topic=287.0>
# Further modified by pklaus, at <https://gist.github.com/pklaus/960672>
# Forked and mostly replaced by W-Floyd, <https://gist.github.com/W-Floyd/20a4c16ceb1e008cb995b7ff7dcc0a2a>

###############################################################################

TUNNELNAME='he-ipv6'

DEVNAME="$(ip route | grep default | tr -s ' ' | cut -d ' ' -f 5 | head -n 1)"
#DEVNAME='tun0' # If using a VPN to a static address, since I'm too lazy to get it working behind a NAT.

LOCAL_IPV4="$(ip addr show "${DEVNAME}" | grep 'inet ' | tr -s ' ' | cut -d ' ' -f 3 | sed 's#/.*##')"

echo -n "Getting external IP"
EXTERNAL_IPV4="$(curl -s 'https://canihazip.com/s')"
echo ": ${EXTERNAL_IPV4}"

# The username you use to login at tunnelbroker.net
HEUSER='you_user_name'

# This 'Update Key' can be found on the 'Advanced' tab of the tunnel details page.
HEKEY='your_update_key'

# The 'Tunnel ID' from the tab IPv6 tunnel on the tunnel details page.
HETUNNEL='your_tunnel_id'

# Tunnel settings
HESERVER4END='216.66.84.42'
HECLIENT6END='2001:470:1f12:c78::2/64'

###############################################################################
# Get root permission
###############################################################################

sudo true || exit 1

###############################################################################
# Remove the interface if it exists
###############################################################################

if [ "$(grep "${TUNNELNAME}" <<< "$(ifconfig -l | tr ' ' '\n' )")" ]; then

    echo "Removing previous tunnel."

    sudo ip -6 route del ::/0 dev "${TUNNELNAME}"
    sudo ip link set "${TUNNELNAME}" down
    sudo ip tunnel del "${TUNNELNAME}"

    echo "Done removing previous tunnel."

fi

###############################################################################

echo "Updating IPv4 tunnel endpoint setting with Hurricane Electric."

curl "https://${HEUSER}:${HEKEY}@ipv4.tunnelbroker.net/nic/update?hostname=${HETUNNEL}&myip=${EXTERNAL_IPV4}" 1&> /dev/null

echo "Setting up tunnel."

sudo ip tunnel add "${TUNNELNAME}" mode sit remote "${HESERVER4END}" local "${LOCAL_IPV4}" ttl 255
sudo ip link set "${TUNNELNAME}" up
sudo ip addr add "${HECLIENT6END}" dev "${TUNNELNAME}"
sudo ip -6 route add ::/0 dev "${TUNNELNAME}"

echo "Done setting up tunnel."

exit

Huh, looks like I changed pretty much everything...

Could you maybe also change the ifconfig commands to use the actual ip commands, so it's not platform specific?
A lot of distros are not using that anymore and it's considered deprecated in some cases.