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/
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.
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
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:
Easy way to grab the IP address of a machine for easy script use. If needed a "| grep -v 127.0.0.1" at the end will suppress localhost.
HP UX doesn't have a -a switch in the ifconfig command.
This line emulates the same result shown in Solaris, AIX or Linux
the below command create a alias for share your internet connection with another.
ifconfig eth0:1 192.168.0.1/24
Its obviously necessary too activate the iptables post-routing and ip forwarding, as root:
modprobe iptable_nat
iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
echo 1 > /proc/sys/net/ipv4/ip_forward
Be sure that the alias 192.168.0.0/24 is not your active real ip range
Get the line containing "inet addr:" and the line before that, get down to only the first line, and then get the first word on that line, which should be the interface.
Sometimes, you don't really care about all the other information that ifconfig spits at you (however useful it may otherwise be). You just want an IP. This strips out all the crap and gives you exactly what you want.
Gets the internal and external IP addresses of all your interfaces, or the ones given as arguments
Will return your internal IP address.
The example command deletes all aliases for network interface 'em0' assuming that the aliases have netmask of 255.255.255.255 and the master IP has some other netmask (such as 255.255.255.0). See here -> http://my.galagzee.com/2009/07/22/deleting-all-network-interface-aliases/ for more on the rationale of this command.
The initial version of this command also outputted extra empty lines, so it went like this:
192.168.166.48
127.0.0.1
This happened on Ubuntu, i haven't tested on anything else.
and, a lot uglier, with sed:
ifconfig | sed -n '/inet addr:/s/[^:]\+:\(\S\+\).*/\1/p'
Edit:
Wanted to be shorter than the perl version. Still think that the perl version is the best..
Fetches the IPs and ONLY the IPs from ifconfig. Simplest, shortest, cleanest.
Perl is too good to be true...
(P.S.: credit should go to Peteris Krumins at catonmat.net)