MacChanger

From Hackerpedia

This tool is a scriptkiddy tool, that allows you to change the mac address to the network adapter of your choice. Please note that this is temporary, and after your shutdown/restart your machine the mac address goes back to normal. Out of all seriousness this tool isn't needed. if you would like to change your mac address to the network adapter of your choice just use the "ifconfig" command. it has many options.

ifconfig eth0 down

ifconfig eth0 hw ether 00:11:22:33:44:55

ifconfig eth0 up

this makes the network adapter eth0 change its mac address to 00:11:22:33:44:55. this can also be done with wireless cards as well

ifconfig wlan0 down

ifconfig wlan0 hw ether 00:11:22:33:44:55

ifconfig wlan0 up