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

Question

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

Sample output:

bash-3.00# ifconfig eth0        
eth0      Link          


        

Answer 1

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