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

Commands tagged math from sorted by
Terminal - Commands tagged math - 13 results
dc -e '10 [q]sq[dd1=q1-lxx*]dsxxp'
2011-02-16 19:00:21
User: mwgamera
Tags: math factorial
0

More readable version of factorial calculation using standard desktop calculator instead of bc.

echo $(($(seq -s* 10)))
2011-02-10 18:44:53
User: minduim
Functions: echo seq
Tags: math factorial
1

Same as the seq/bc solution but without bc.

for((r=1;r<10;r++));do v=1;echo -n "$v ";for((c=1;c<$r;c++));do v2=$(($(echo "$v*($r-$c)/$c")));echo -n "$v2 ";v=$v2;done;echo;done
2011-02-10 18:38:04
User: flatcap
Functions: echo
Tags: bash math
0

http://en.wikipedia.org/wiki/Pascal%27s_triangle

This one's for bartonski. Enjoy.

132 characters. I'm sure we can do better.

Note: after row 64 we overflow integer maths.

echo $(( $(echo 1 "* "{2..10}) ))
seq -s^2+ 11 |rev| cut -d'+' -f2- | rev | bc
2011-02-10 08:41:14
User: rubenmoran
Functions: cut rev seq
Tags: seq sum math
-2

I can't put the last ^2 with seq, so I reverse it to delete the last +N. So for doing sum(N^2) you have to do sum((N+1)^2). Must be a better way.

seq -s* 10 |bc
seq 1 2 99999999 | sed 's!^!4/!' | paste -sd-+ | bc -l
2011-02-09 23:36:07
User: flatcap
Functions: bc paste sed seq
Tags: sed seq bc paste math
0

Calculate pi from the infinite series 4/1 - 4/3 + 4/5 - 4/7 + ...

This expansion was formulated by Gottfried Leibniz: http://en.wikipedia.org/wiki/Leibniz_formula_for_pi

I helped rubenmoran create the sum of a sequence of numbers and he replied with a command for the sequence: 1 + 2 -3 + 4 ...

This set me thinking. Transcendental numbers!

seq provides the odd numbers 1, 3, 5

sed turns them into 4/1 4/3 4/5

paste inserts - and +

bc -l does the calculation

Note: 100 million iterations takes quite a while. 1 billion and I run out of memory.

seq 1000 | paste -sd+- | bc
seq 10 | paste -sd* | bc
echo 'obase=16; C+F' | bc
2010-04-14 20:35:31
User: rkulla
Functions: echo
Tags: hex bc math asm
4

To do hex to binary: echo 'ibase=16; obase=2; 16*16' | bc # prints: 111100100

To do 16*16 from decimal to hex: echo 'ibase=10; obase=16; 16*16' | bc # prints: 100

You get the idea... Alternatively, run bc in interactive mode (see man page)

perl -MStatistics::Descriptive -alne 'my $stat = Statistics::Descriptive::Full->new; $stat->add_data(@F[1..4]); print $stat->variance' filename
2010-04-02 21:16:12
User: alperyilmaz
Functions: perl
1

In this example, file contains five columns where first column is text. Variance is calculated for columns 2 - 5 by using perl module Statistics::Descriptive. There are many more statistical functions available in the module.

year=2010; math=`echo "$year%4" | bc`; [ ! -z $year ] && [ $math -eq 0 ] && echo "$year is leap year!" || echo "$year isn't leap year";
expr 512 \* 7
2009-09-23 19:11:38
User: chuckr
Functions: expr
Tags: math expr
4

expr will give you a quick way to do basic math from the CLI. Make sure you escape things like * and leave a space between operators and digits.