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

user_29405 0
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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.

command-line-interface linux regex
19 Answers

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).

Robert_Gamble_252220

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
user_146480

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

ifconfig eth0 | awk '/HWaddr/ {print $5}'
albertb_267150

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

user_1961330 
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.
user_123962770 
ifconfig | grep -i hwaddr | cut -d ' ' -f11
user_24852650

ifconfig en0 | grep ether - for wired mac address

ifconfig en1 | grep ether - for wireless mac address

user_56823360

this worked for me 

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

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

user_70274310
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