Randomise your ethernet mac address for bypassing free wifi time limits.

randmac.sh

#!/bin/bash

if=${1-en1}

function get_if_mac() {
    local if=$1
    ifconfig en1 | grep ether | sed -e 's/^[[:space:]]ether //'
}

mac=$(get_if_mac $if)

while true; do
    new_mac=$(openssl rand -hex 6 | sed 's/\(..\)/\1:/g; s/.$//')
    echo "$mac -> $new_mac"

    sudo ifconfig $if ether $new_mac
    mac=$(get_if_mac $if)
    [ ${new_mac} = ${mac} ] && break
done