Best way to extract MAC address from ifconfig's output?

RegexLinuxCommand Line-Interface

Regex Problem Overview

What is the best way to extract the MAC address from ifconfig's output?

Sample output:

bash-3.00# ifconfig eth0        
eth0      Link encap:Ethernet  HWaddr 1F:2E:19:10:3B:52    
          inet addr:127.0.0.66  Bcast:127.255.255.255  Mask:255.0.0.0    
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          ....
          ....

Should I use cut, AWK or anything else, and what are the merits and demerits of one method over the other.

Regex Solutions

Solution 1 - Regex

You can do a cat under /sys/class/

cat /sys/class/net/*/address

Specifically for eth0

cat /sys/class/net/eth0/address

Solution 2 - Regex

I would use:

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

The -o will cause grep to only print the part of the line that matches the expression. [[:xdigit:]]{1,2} will match 1 or 2 hexidecimal digits (Solaris doesn't output leading zeros).

Solution 3 - Regex

I like using /sbin/ip for these kind of tasks, because it is far easier to parse:

$ ip link show eth0
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000
    link/ether 00:0c:29:30:21:48 brd ff:ff:ff:ff:ff:ff

You can trivially get the mac address from this output with awk:

$ ip link show eth0 | awk '/ether/ {print $2}'
00:0c:29:30:21:48

If you want to put a little more effort in, and parse more data out, I recommend using the -online argument to the ip command, which will let you treat every line as a new device:

$ ip -o link 
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 16436 qdisc noqueue \    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000\    link/ether 00:0c:29:30:21:48 brd ff:ff:ff:ff:ff:ff
3: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 1000\    link/ether 00:0c:29:30:21:52 brd ff:ff:ff:ff:ff:ff
4: tun0: <POINTOPOINT,MULTICAST,NOARP,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast qlen 100\    link/[65534] 
5: sit0: <NOARP> mtu 1480 qdisc noop \    link/sit 0.0.0.0 brd 0.0.0.0

Solution 4 - Regex

Not sure whether there really are any advantages, but you can simply use awk:

ifconfig eth0 | awk '/HWaddr/ {print $5}'

Solution 5 - Regex

Since the OP's example refers to Bash, here's a way to extract fields such as HWaddr without the use of additional tools:

x=$(ifconfig eth0) && x=${x#*HWaddr } && echo ${x%% *}

In the 1st step this assigns the ouput of ifconfig to x. The 2nd step removes everything before "HWaddr ". In the final step everything after " " (the space behind the MAC) is removed.

Reference: http://www.gnu.org/software/bash/manual/bashref.html#Shell-Parameter-Expansion

Solution 6 - Regex

For Ubuntu/Debian

ifconfig | grep HW | awk '{print $5}'

For Rhat or CentOs try

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

Solution 7 - Regex

I prefer the method described here (with slight modification): http://www.askdavetaylor.com/how_do_i_figure_out_my_ip_address_on_a_mac.html

ifconfig | grep "inet " | grep -v 127.0.0.1 | cut -d " " -f2

Which you can then alias to a short 'myip' command for future use:

echo "alias myip=\"ifconfig | grep 'inet ' | grep -v 127.0.0.1 | cut -d ' ' -f2\"" >> ~/.bash_profile

Solution 8 - Regex

How about this one:

ifconfig eth0 | grep -Eo ..\(\:..\){5}

or more specifically

ifconfig eth0 | grep -Eo [:0-9A-F:]{2}\(\:[:0-9A-F:]{2}\){5}

and also a simple one

ifconfig eth0 | head -n1 | tr -s ' ' | cut -d' ' -f5`

Solution 9 - Regex

On Ubuntu 14.04 in terminal

ifconfig | grep HW

Solution 10 - Regex

ifconfig en1 | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'
  • Replace "en1" with the name of the nic card "eth0" or remove altogether "en1" - easy and useful solution.

Solution 11 - Regex

Note: on OS X eth0 may not work. Use p2p0:

ifconfig p2p0 | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'

Solution 12 - Regex

This works for me on Mac OS X:

ifconfig en0 | grep -Eo ..\(\:..\){5}

So does:

ifconfig en0 | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'

Both are variations of examples above.

Solution 13 - Regex

ifconfig | grep -i hwaddr | cut -d ' ' -f11

Solution 14 - Regex

Nice and quick one:

ifconfig eth0 | grep HWaddr | cut -d ' ' -f 11

Solution 15 - Regex

I needed to get MAC address of the active adapter, so ended up using this command.

ifconfig -a | awk '/^[a-z]/ { iface=$1; mac=$NF; next } /inet addr:/ { print mac }' | grep -o -E '([[:xdigit:]]{1,2}:){5}[[:xdigit:]]{1,2}'

Hope it helps.

Solution 16 - Regex

ifconfig en0 | grep ether - for wired mac address

ifconfig en1 | grep ether - for wireless mac address

Solution 17 - Regex

this worked for me

ifconfig eth0 | grep -o -E ..:..:..:..:..:..

instead of eth0 you can write the interface you need it's mac address

Solution 18 - Regex

Output of ifconfig:

$ifconfig

eth0      Link encap:Ethernet  HWaddr 00:1b:fc:72:84:12
      inet addr:172.16.1.13  Bcast:172.16.1.255  Mask:255.255.255.0
      inet6 addr: fe80::21b:fcff:fe72:8412/64 Scope:Link
      UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
      RX packets:638661 errors:0 dropped:20 overruns:0 frame:0
      TX packets:93858 errors:0 dropped:0 overruns:0 carrier:2
      collisions:0 txqueuelen:1000
      RX bytes:101655955 (101.6 MB)  TX bytes:42802760 (42.8 MB)
      Memory:dffc0000-e0000000

lo        Link encap:Local Loopback
      inet addr:127.0.0.1  Mask:255.0.0.0
      inet6 addr: ::1/128 Scope:Host
      UP LOOPBACK RUNNING  MTU:16436  Metric:1
      RX packets:3796 errors:0 dropped:0 overruns:0 frame:0
      TX packets:3796 errors:0 dropped:0 overruns:0 carrier:0
      collisions:0 txqueuelen:0
      RX bytes:517624 (517.6 KB)  TX bytes:517624 (517.6 KB)

The best way to extract MAC address is:

ifconfig | sed '1,1!d' | sed 's/.*HWaddr //' | sed 's/\ .*//' | sed -e 's/:/-/g' > mac_address

Solution 19 - Regex

Use:

ifconfig eth0 | grep HWaddr

or

ifconfig eth0 |grep HWaddr

This will pull just the MAC address and nothing else.

You can change your MAC address to whatever you want:

ifconfig eth0 down,
ifconfig eth0 hw ether (new MAC address),
ifconfig eth0 up
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