Get MAC address using shell script

Question

Currently all the solution mentioned for getting the MAC address always use eth0. But what if instead of eth0 my interfaces start with eth1. Also on OS X the interface names are different.
Also the interface eth0 may be present but is unused. i.e. not active, it doesn't have an IP.

So is there a way I could get the MAC address for the first available interface that is Active.(i.e. it has an inet address, I even don't want one having inet6).

For E.g

eth0      Link encap:Ethernet  HWaddr <some addr>
          inet6 addr: <some addr> Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:123
          RX packets:123 errors:123 dropped:123 overruns:123 frame:123
          TX packets:123 errors:123 dropped:123 overruns:123 carrier:123
          collisions:123 txqueuelen:123 
          RX bytes:123 (123 MB)  TX bytes:123 (123 KB)
          Interrupt:123 Memory:00000000-00000000

eth1      Link encap:Ethernet  HWaddr <some addr>
          inet addr:<some addr>  Bcast:<some addr>  Mask:<some addr>
          inet6 addr: <some addr> Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:123 Metric:123
          RX packets:123 errors:123 dropped:123 overruns:123 frame:123
          TX packets:123 errors:123 dropped:123 overruns:123 carrier:123
          collisions:123 txqueuelen:123 
          RX bytes:123 (123 MB)  TX bytes:123 (123 KB)
          Interrupt:123 Memory:00000000-00000000

NOTE : I have changed the values of the output.

So in this case I want the HWaddr for eth1 and not eth0. How do I find it ? Also it should work on all the Linux flavours.

Answer 1

Observe that the interface name and the MAC address are the first and last fields on a line with no leading whitespace.

If one of the indented lines contains inet addr: the latest interface name and MAC address should be printed.

ifconfig -a |
awk '/^[a-z]/ { iface=$1; mac=$NF; next }
    /inet addr:/ { print iface, mac }'

Note that multiple interfaces could meet your criteria. Then, the script will print multiple lines. (You can add ; exit just before the final closing brace if you always only want to print the first match.)

Answer 2

Here's an alternative answer in case the ones listed above don't work for you. You can use the following solution(s) as well, which was found here:

ip addr

OR

ip addr show

OR

ip link

All three of these will show your MAC address(es) next to link/ether. I stumbled on this because I had just done a fresh install of Debian 9.5 from a USB stick without internet access, so I could only do a very minimal install, and received

-bash: ifconfig: command not found

when I tried some of the above solutions. I figured somebody else may come across this problem as well. Hope it helps.

Answer 3

I know that is a little bit dated, but with basic commands, we can take the mac address of an interface:

ip link show eth0 | grep link/ether | awk '{print $2}'

Have a nice day!

Answer 4

Get MAC adress for eth0:

$ cat /etc/sysconfig/network-scripts/ifcfg-eth0 | grep HWADDR | cut -c 9-25

Example:

[me@machine ~]$ cat /etc/sysconfig/network-scripts/ifcfg-eth0 | grep HWADDR | cut -c 9-25
55:b5:00:10:be:10

Answer 5

Simply run:

ifconfig | grep ether | cut -d " " -f10

OR

ip a | grep ether | cut -d " " -f6

These two example commands will grep all lines with "ether" string and cut the mac address (that we need) following the number spaces (specified in the -f option) of the grepped portion.

Tested on different Linux flavors