Comments on: Bash one liner to randomize lines in file

By: Jadu Saikia

Jadu Saikia — Sun, 10 Jan 2010 13:33:44 +0000

‘Shuf’ and ‘rl’ are good options here. Here are two small tutorial on my blog:

rl:
http://unstableme.blogspot.com/2010/01/randomize-lines-using-linux-rl-command.html

shuf:
http://unstableme.blogspot.com/2009/10/linux-shuf-command-generate-random.html

By: Moses

Moses — Tue, 10 Nov 2009 17:16:48 +0000

“why don’t you use shuf? Why not use sort -R?”
If I had shuf, or if my local /bin/sort supported -R, I would use it. But I don’t, which is why I’m using something fork-y in bash.

“why don’t you just get shuf?”
Because I don’t have root and/or gcc on every machine I touch.

HOWEVER, with what was mentioned above, I can make shuf:

echo -e ‘#!/bin/bash’”\n”‘while read -r LINE; do echo “$RANDOM $LINE”; done |sort |sed -r ‘”’s/^[0-9]+ //’” > ~/bin/shuf
chmod 0755 ~/bin/shuf

Now I can put |shuf into my chains of pipes.

By: manoflinux

manoflinux — Wed, 23 Sep 2009 20:01:35 +0000

this actually works for me. its simpler and uses colrm which rocks.

for i in `cat mapslist.txt`; do echo `printf “%08d” $RANDOM` $i; done | sort | colrm 1 10 >mapslist.txt.rand; mv mapslist.txt mapslist.old; mv mapslist.txt.rand mapslist.txt;

By: Arthur

Arthur — Sun, 20 Sep 2009 11:33:23 +0000

sort -R will only work if the lines are unique. If there are duplicate lines, sort -R will put them next to each other.

shuf on the other hand will sufficiently randomize a list, including NOT putting duplicate lines next to each other.

By: swordfish

swordfish — Mon, 03 Aug 2009 01:30:33 +0000

none of these worked for me. i found the solution on a far away google result : (be careful despite this is the first google result , the formatting sucks and copy-paste may give errors)

awk ‘BEGIN {srand()} {print int(rand()*1000000) “\t” $0}’ file | sort -n | cut -f 2-

By: gabriellllo

gabriellllo — Mon, 06 Jul 2009 23:08:53 +0000

Great tip!

Since I had numbers in my file, I used awk instead of sed, since I found it easier:
for i in `cat list_to_randomize.txt`; do echo “$RANDOM $i”; done | sort | awk ‘{print $2}’ > randomized_list.txt

Thanks a lot for this page!

By: Boris Abramov

Boris Abramov — Thu, 25 Jun 2009 12:17:39 +0000

sort -R

By: bart

bart — Fri, 29 May 2009 01:31:39 +0000

How about:
awk ‘BEGIN{srand()}{print rand(),$0}’ SOMEFILE | sort -n | cut -d ‘ ‘ -f2-

By: (Pseudo) aleatori en BASH | L’home dibuixat

(Pseudo) aleatori en BASH | L’home dibuixat — Tue, 12 May 2009 17:01:53 +0000

[...] té una funció $RANDOM que genera un nombre pseudo-aleatori en cada [...]

By: Dougal

Dougal — Sun, 03 May 2009 20:14:08 +0000

My previous comment got screwed up by the formatting…

First part: “while read i ; do echo “$RANDOM $i”; done randorder.txt”