Or this:
#!/bin/sh
INSTALL_PATH="/etc/init.d/randomize_mac"
echo "Creating MAC randomizer script..."
cat << 'EOF' > $INSTALL_PATH
#!/bin/sh /etc/rc.common
START=99
start() {
generate_random_mac() {
echo $(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))
}
change_mac() {
local iface=$1
local new_mac=$(generate_random_mac)
ip link set dev $iface down
ip link set dev $iface address $new_mac
ip link set dev $iface up
}
for iface in $(ip link show | grep -E '^[0-9]+:' | cut -d ':' -f 2 | cut -d ' ' -f 2); do
if [ "$iface" != "lo" ]; then
change_mac $iface
fi
done
}
EOF
echo "Making MAC randomizer script executable..."
chmod +x $INSTALL_PATH
echo "Success!"
echo "Enabling MAC randomizer script to run at boot time..."
/etc/init.d/randomize_mac enable
echo "Success!"
echo "Deleting installation script..."
rm -- "$0"
Here is example of output of this command:
echo $(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%256)))
Output:
localhost:~# echo $(printf '%02x' $((RANDOM%256)))
":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%0
2x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%2
56)))":"$(printf '%02x' $((RANDOM%256)))":"$(print
f '%02x' $((RANDOM%256)))
a7:03:f2:fa:45:5d
localhost:~# echo $(printf '%02x' $((RANDOM%256)))
":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%0
2x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%2
56)))":"$(printf '%02x' $((RANDOM%256)))":"$(print
f '%02x' $((RANDOM%256)))
f5:3f:8b:6e:f9:84
localhost:~# echo $(printf '%02x' $((RANDOM%256)))
":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%0
2x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%2
56)))":"$(printf '%02x' $((RANDOM%256)))":"$(print
f '%02x' $((RANDOM%256)))
e8:db:17:37:29:fd
localhost:~# echo $(printf '%02x' $((RANDOM%256)))
":"$(printf '%02x' $((RANDOM%256)))":"$(printf '%0
2x' $((RANDOM%256)))":"$(printf '%02x' $((RANDOM%2
56)))":"$(printf '%02x' $((RANDOM%256)))":"$(print
f '%02x' $((RANDOM%256)))