What's an easy way to read random line from a file in Unix command line?

Question

What's an easy way to read random line from a file in Unix command line?

Answer 1

cat + perl <http://snippets.openminds.be/posts/show/8&gt;

edit: perl -e 'srand; rand($.) < 1 && ($line = $_) while <>; print $line;' filename

thanks Mr. Muskrat

Answer 2

Here's a simple Python script that will do the job:

import random, sys
lines = open(sys.argv[1]).readlines()
print(lines[random.randint(0, len(lines))])

Usage:

python randline.py file_to_get_random_line_from

Answer 3

using a bash script:

#!/bin/bash
# replace with file to read
FILE=tmp.txt
# count number of lines
NUM=$(wc - l < ${FILE})
# generate random number in range 0-NUM
let X=${RANDOM} % ${NUM} + 1
# extract X-th line
sed -n ${X}p ${FILE}

Answer 4

Single bash line:

sed -n $((1+$RANDOM%`wc -l test.txt | cut -f 1 -d ' '`))p test.txt

Slight problem: duplicate filename.

Answer 5

There is a utility called rl. In Debian it's in the randomize-lines package that does exactly what you want.

Or you can use shuf:

shuf -n 1 $FILE

Answer 6

Another alternative:

head -$((${RANDOM} % `wc -l < file` + 1)) file | tail -1