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.

OpenID
or
Sign in Register

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

Hide

Credits

Site by David Winterbottom (user root).

Fibonacci With Case

Terminal - Fibonacci With Case
fib(){ case $1 in 0)echo 0;;1)echo 1;;[0-9]*)echo $[$(fib $[$1-2])+$(fib $[$1-1])];;*)exit 1;;esac;}
2010-06-28 19:41:44
User: kzh
2
Up
Down
Fibonacci With Case

Returns the '$1'th Fibonacci number.

Show sample output | Add to favourites | Report as malicious

Alternatives

There are 7 alternatives - vote for the best!

Terminal - Alternatives

Know a better way?

If you can do better, submit your command here.

What others think

recursively finding fibonacci sequences is a really good way to freeze any system up

use a for loop for a more efficient calculation

Comment by amanharan 155 weeks and 1 day ago

If one were worried about efficiency, then one should not use a shell script.

This was quick to write. Thanks for the input.

Comment by kzh 155 weeks and 1 day ago
fib(){ k=0; l=1; for i in `seq 1 $1`; do t=$l; l=$(($l + $k)); k=$t; done; echo $k;}

also quick to write, but much faster

Comment by fpunktk 155 weeks and 1 day ago

fpunktk: 93th and some others afterwards are negative, why is that?

Comment by alperyilmaz 155 weeks and 1 day ago

I had never really used bash case statements before and was trying them out. If I really wanted to use large numbers, I would have done:

python -c 'def fib(n):

if n not in fibs:fibs[n]=fib(n-1)+fib(n-2)

return fibs[n]

import sys;fibs={0:0,1:1};print fib(int(sys.argv[1]))' 7

13

Comment by kzh 155 weeks and 1 day ago

Your point of view

You must be signed in to comment.

Related sites and podcasts