Get MAC address using shell script

问题:

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.

回答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.)

回答2:

You can do as follows

ifconfig <Interface ex:eth0,eth1> | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'

Also you can get MAC for all interface as follows

cat /sys/class/net/*/address

For particular interface like for eth0

cat /sys/class/net/eth0/address

回答3:

The best Linux-specific solution is to use sysfs:

$ IFACE=eth0
$ read MAC </sys/class/net/$IFACE/address
$ echo $IFACE $MAC
eth0 00:ab:cd:12:34:56

This method is extremely clean compared to the others and spawns no additional processes since read is a builtin command for POSIX shells, including non-BASH shells. However, if you need portability to OS X, then you'll have to use ifconfig and sed methods, since OS X does not have a virtual filesystem interface like sysfs.

回答4:

$ ip route show default | awk '/default/ {print $5}'

return: eth0 (my online interface)

$ cat /sys/class/net/$(ip route show default | awk '/default/ {print $5}')/address

return: ec:a8:6b:bd:55:05 (macaddress of the eth0, my online interface)

Terminal image

回答5:

On a modern GNU/Linux system you can see the available network interfaces listing the content of /sys/class/net/, for example:

$ ls /sys/class/net/
enp0s25  lo  virbr0  virbr0-nic  wlp2s0

You can check if an interface is up looking at operstate in the device directory. For example, here's how you can see if enp0s25 is up:

$ cat /sys/class/net/enp0s25/operstate
up

You can then get the MAC address of that interface with:

$ cat /sys/class/net/enp0s25/address 
ff:00:ff:e9:84:a5

For example, here's a simple bash script that prints MAC addresses for active interfaces:

#!/bin/bash
# getmacifup.sh: Print active NICs MAC addresses
D='/sys/class/net'
for nic in $( ls $D )
do
    echo $nic
    if  grep -q up $D/$nic/operstate
    then
        echo -n '   '
        cat $D/$nic/address
    fi
done

And here's its output on a system with an ethernet and a wifi interface:

$ ./getmacifup.sh
enp0s25
   ff:00:ff:e9:84:a5
lo
wlp2s0

For details see the Kernel documentation

---

Remember also that from 2015 most GNU/Linux distributions switched to systemd, and don't use ethX interface naming scheme any more - now they use a more robust naming convention based on the hardware topology, see:

• Predictable Network Interface Names
• systemd/src/udev/udev-builtin-net_id.c

回答6:

oh, if you want only the mac ether mac address, you can use that:

ifconfig | grep "ether*" | tr -d ' ' | tr -d '\t' | cut -c 6-42

(work on macintosh)

• ifconfig -- get all info
• grep -- keep the line with address
• tr -- clean all
• cut -- remove the "ether" to have only the address

回答7:

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

回答8:

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!

回答9:

None of the above worked for me because my devices are in a balance-rr bond. Querying either would say the same MAC address with ip l l, ifconfig, or /sys/class/net/${device}/address, so one of them is correct, and one is unknown.

But this works if you haven't renamed the device (any tips on what I missed?):

udevadm info -q all --path "/sys/class/net/${device}"

And this works even if you rename it (eg. ip l set name x0 dev p4p1):

cat /proc/net/bonding/bond0

or my ugly script that makes it more parsable (untested driver/os/whatever compatibility):

awk -F ': ' '
         $0 == "" && interface != "" {
            printf "%s %s %s\n", interface, mac, status;
            interface="";
            mac=""
         }; 
         $1 == "Slave Interface" {
            interface=$2
         }; 
         $1 == "Permanent HW addr" {
            mac=$2
         };
         $1 == "MII Status" {
            status=$2
         };
         END {
            printf "%s %s %s\n", interface, mac, status
         }' /proc/net/bonding/bond0

回答10:

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.

回答11:

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