Как узнать MAC-адрес сетевой карты в Debian, CentOS, FreeBSD (или Ubuntu, RedHat)

$ sudo ifconfig
xl0: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1500
        options=80008<VLAN_MTU,LINKSTATE>
        ether 00:60:97:5b:3c:fd
        inet 192.168.0.1 netmask 0xffffff00 broadcast 192.168.0.255
        media: Ethernet autoselect (100baseTX)
        status: active

$ sudo ifconfig -a
eth0      Link encap:Ethernet  HWaddr fe:16:3e:68:fc:95
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          inet6 addr: fe80::fc16:3eff:fe68:fc95/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:239525695 errors:0 dropped:0 overruns:0 frame:0
          TX packets:95288283 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:1706073511 (1.5 GiB)  TX bytes:669868294 (638.8 MiB)
          Interrupt:246

$ sudo /sbin/ifconfig -a
eth0      Link encap:Ethernet  HWaddr FE:16:3E:68:FC:FC
          inet addr:192.168.0.1  Bcast:192.168.0.255  Mask:255.255.255.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:287136 errors:0 dropped:0 overruns:0 frame:0
          TX packets:132466 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:69584534 (66.3 MiB)  TX bytes:9595586 (9.1 MiB)
          Interrupt:177 Base address:0xc000