#!/usr/bin/env bash
#  vim:ts=4:sts=4:sw=4:et
#
#  Author: Hari Sekhon
#  Date: 2020-06-24 00:45:44 +0100 (Wed, 24 Jun 2020)
#
#  https://github.com/harisekhon/bash-tools
#
#  License: see accompanying Hari Sekhon LICENSE file
#
#  If you're using my code you're welcome to connect with me on LinkedIn and optionally send me feedback to help steer this or other code I publish
#
#  https://www.linkedin.com/in/harisekhon
#

# Generates a random alphanumeric string of the given length
#
# pwgen is also a good option, but may not always be installed, hence this is more portable

set -euo pipefail
[ -n "${DEBUG:-}" ] && set -x
#srcdir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"

len="${1:-32}"

if ! [[ "$len" =~ ^[[:digit:]]+$ ]]; then
    echo "invalid string len given as first argument to ${0##*/}" >&2
    exit 1
fi

# fixes illegal byte error in tr / sed etc
export LC_ALL=C

#tr -duc 'A-Za-z0-9' < /dev/urandom | fold -w "$len" | head -n1
tr -duc '[:alnum:]' < /dev/urandom | head -c "$len" || :  # head returns error code 141 but succeeds