What's this?

commandlinefu.com is the place to record those command-line gems that you return to again and again.

Delete that bloated snippets file you've been using and share your personal repository with the world. That way others can gain from your CLI wisdom and you from theirs too. All commands can be commented on, discussed and voted up or down.

Get involved!

You can sign-in using OpenID credentials, or register a traditional username and password.

First-time OpenID users will be automatically assigned a username which can be changed after signing in.

UpGuard checks and validates configurations for every major OS, network device, and cloud provider.

Stay in the loop…

Follow the Tweets.

Every new command is wrapped in a tweet and posted to Twitter. Following the stream is a great way of staying abreast of the latest commands. For the more discerning, there are Twitter accounts for commands that get a minimum of 3 and 10 votes - that way only the great commands get tweeted.

» http://twitter.com/commandlinefu
» http://twitter.com/commandlinefu3
» http://twitter.com/commandlinefu10

Subscribe to the feeds.

Use your favourite RSS aggregator to stay in touch with the latest commands. There are feeds mirroring the 3 Twitter streams as well as for virtually every other subset (users, tags, functions,…):

Subscribe to the feed for:



May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

Top Tags



Find MAC address of Active Eth connection

Terminal - Find MAC address of Active Eth connection
/sbin/ifconfig|grep -B 1 inet |head -1 | awk '{print $5}'
2010-04-22 06:35:29
User: octopus
Functions: awk grep head
Find MAC address of Active Eth connection


There are 2 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

not every machine has only one NIC...

Comment by buzzy 417 weeks and 3 days ago

This is not for one mac address. it will find the active eth connection and show you the mac address.

Comment by octopus 417 weeks and 3 days ago

It shows the first ethernet connection. Could be that eth0 is not active, but eth1. And on FreeBSD it won't work.What you need to do is actually search for the MAC adress:

/sbin/ifconfig|grep ..:..:..:..:..:..|awk '{print $1" "$NF}'

This will show the name and the IP adress.

Comment by houghi 417 weeks and 3 days ago

Here's a perlized variant:

/sbin/ifconfig|perl -lane 'print "$F[0] $F[$#F]" if /(..:){5}/'

though on a BSD box, netstat may be saner (with this particular command):

/bin/netstat -i|perl -lane 'print "$F[0] $F[3]" if /(..:){5}/'
Comment by zerokey 417 weeks and 3 days ago

Your point of view

You must be signed in to comment.