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May 19, 2015 - A Look At The New Commandlinefu
I've put together a short writeup on what kind of newness you can expect from the next iteration of clfu. Check it out here.
March 2, 2015 - New Management
I'm Jon, I'll be maintaining and improving clfu. Thanks to David for building such a great resource!

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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 is 1 alternative - 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 456 weeks and 1 day ago
rl -c 1

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

Comment by Josay 456 weeks and 1 day ago

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

Comment by bwoodacre 456 weeks ago

shuf -n1 file.txt

Comment by sklm 456 weeks ago

even better! shuf is part of GNU coreutils.

Comment by bwoodacre 456 weeks ago

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

Comment by andrew112358 456 weeks ago

Your point of view

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