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

port scan using parallel

Terminal - port scan using parallel
seq 1 255 | parallel -j+0 'nc -w 1 -z -v 192.168.1.{} 80'
2011-06-11 14:40:51
User: devrick0
Functions: seq
1
port scan using parallel

It takes over 5 seconds to scan a single port on a single host using nmap

time (nmap -p 80 192.168.1.1 &> /dev/null)

real 0m5.109s

user 0m0.102s

sys 0m0.004s

It took netcat about 2.5 minutes to scan port 80 on the class C

time (for NUM in {1..255} ; do nc -w 1 -z -v 192.168.1.${NUM} 80 ; done &> /dev/null)

real 2m28.651s

user 0m0.136s

sys 0m0.341s

Using parallel, I am able to scan port 80 on the entire class C in under 2 seconds

time (seq 1 255 | parallel -j255 'nc -w 1 -z -v 192.168.1.{} 80' &> /dev/null)

real 0m1.957s

user 0m0.457s

sys 0m0.994s

Alternatives

There are 11 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

Your point of view

You must be signed in to comment.

Related sites and podcasts