Generates a random password, after http://xkcd.com/936/.

password.sh

#!/bin/bash

#
# Generates a random password, after http://xkcd.com/936/.
#
# -f [words file, one per line; default /usr/share/dict/words]
# -w [number of words; default 3]
# -n [min number of characters per word; default 6]
# -x [max number of characters per word; default 10]
#

set -u -e

WORDS=/usr/share/dict/words
NUM_WORDS=4
MIN_CHARS=6
MAX_CHARS=10

while getopts f:w:n:x: OPTION
do
    case ${OPTION} in
        f) WORDS=${OPTARG};;
        w) NUM_WORDS=${OPTARG};;
        n) MIN_CHARS=${OPTARG};;
        x) MAX_CHARS=${OPTARG};;
    esac
done

egrep "^[a-z]{${MIN_CHARS},${MAX_CHARS}}\$" ${WORDS} \
    | shuf -n${NUM_WORDS} | xargs