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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
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2010-09-24 - OAuth and pagination problems fixed
Apologies for the delay in getting Twitter's OAuth supported. Annoying pagination gremlin also fixed.




Pick a random line from a file

Terminal - Pick a random line from a file
sort -R file.txt | head -1
2009-07-23 22:24:52
User: dfego
Functions: head sort
Pick a random line from a file


There are 2 alternatives - vote for the best!

Terminal - Alternatives
shuf -n1 file.txt
perl -e 'rand($.) < 1 && ($line = $_) while <>;'
2011-04-25 21:28:26
Functions: perl
Tags: perl knuth

This is from perldoc -q random.*line, which says:

This has a significant advantage in space over reading the whole file in. You can find a proof of this method in The Art of Computer Programming, Volume 2, Section 3.4.2, by Donald E. Knuth.

Who am I to argue with Don Knuth?

head -$(($RANDOM % $(wc -l < file.txt) +1 )) file.txt | tail -1
2009-07-23 12:00:49
User: sharfah
Functions: head tail wc

prints a random line

shuf file.txt | head -n 1

Know a better way?

If you can do better, submit your command here.

What others think

excellent. i wish -R was a standard option though :(

Comment by recursiverse 296 weeks ago
rl -c 1

(rl stands for "Randomize Lines" and can be easily installed on most distribs when not already done)

Comment by Josay 296 weeks ago

rl is available as package 'randomize-lines' under debian/ubuntu.

Comment by bwoodacre 296 weeks ago

shuf -n1 file.txt

Comment by sklm 295 weeks and 6 days ago

even better! shuf is part of GNU coreutils.

Comment by bwoodacre 295 weeks and 6 days ago

The third one is the only one that doesn't require GNU coreutils.

Comment by andrew112358 295 weeks and 6 days ago

Your point of view

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