Mac address - what is line command to find and active new card

How do you find mac address and active new card.

To see the mac address of the card, type ifconfig. If the card does not show up, then type ifconfig eth0 up (assumming that eth0 is the one not up, which would be the first ethernet card). If its the second, ifconfig eth1 up, etc.... This should show you the mac address and activate the card.