Hide

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.


If you have a new feature suggestion or find a bug, please get in touch via http://commandlinefu.uservoice.com/

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.

Hide

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:

Hide

News

2011-03-12 - Confoo 2011 presentation
Slides are available from the commandlinefu presentation at Confoo 2011: http://presentations.codeinthehole.com/confoo2011/
2011-01-04 - Moderation now required for new commands
To try and put and end to the spamming, new commands require moderation before they will appear on the site.
2010-12-27 - Apologies for not banning the trolls sooner
Have been away from the interwebs over Christmas. Will be more vigilant henceforth.
2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.
Hide

Tags

Hide

Functions

Fetch the Gateway Ip Address

Terminal - Fetch the Gateway Ip Address
netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}'
2010-03-07 01:47:55
User: freethinker
Functions: awk netstat
1
Fetch the Gateway Ip Address

This is to fetch the Gateway Ip Address of a machine. Use the below format to put the value in a variable if you wish to find the gateway ip in a script

GATEWAY=$(netstat -nr | awk 'BEGIN {while ($3!="0.0.0.0") getline; print $2}')

Alternatives

There are 2 alternatives - vote for the best!

Terminal - Alternatives
ip route list match 0.0.0.0/0 | cut -d " " -f 3
2010-03-07 15:41:18
User: BaS
Functions: cut route
2

Better use iproute2 !

/sbin/route -n | grep "^0\.0\.0\.0" | awk '{ print $2 }'
2010-03-07 13:59:57
User: BorneBjoern
Functions: awk grep
0

same thing without loop ;)

Know a better way?

If you can do better, submit your command here.

What others think

Well unfortunately this did not work on my BSD box... but you could us this instead.

For FreeBSD either of these will work.

awk -F '"' '/defaultrouter/{print $2}' /etc/rc.conf

netstat -nr | awk '/default/{ print $2}'

Now on Mac OS X it get's a little trickier because IPv6 is enabled by default. The following works for me.

netstat -nr | awk '/default/{ print $2;exit}'

Oh on FreeBSD there's a third option if your are running bash but it can get messy. This reads the file into the shell as an include script Remember bash is not installed by default on and BSD.

. /etc/rc.conf

echo $defaultrouter

Cheers,

Mikel King

Comment by mikelking 215 weeks and 5 days ago

Pretty cool, I should have actually used the subject line "Fetch the Gateway Ip Address on Linux" ...

Comment by freethinker 215 weeks and 5 days ago

Your point of view

You must be signed in to comment.

Related sites and podcasts