Generate random alphanumeric text DIGITS long.

rnd.sh

#!/bin/bash

# This is a simplified version of this script: https://gist.github.com/earthgecko/3089509 

# "Random numbers in a range, more randomly distributed than $RANDOM 
# which is not very random in terms of distribution of numbers."

# You may want to add a reference to your .bashrc file, e.g.:
# alias rnd="path/to/script/rnd.sh"

# macOS fix, ref: https://github.com/projectzeroindia/CVE-2019-19781/issues/3
export LC_CTYPE=C

if (( $# != 1 )); then
    echo "Script syntax: rnd <number of digits>, e.g. rnd 256";
    echo "Defaulting to 32 digits";
    DIGITS=32
else
    DIGITS=$1
fi
# generate random alphanumeric text DIGITS long
cat /dev/urandom | tr -dc 'a-zA-Z0-9' | fold -w $DIGITS | head -n 1