Listing 3. Password Generator Script

#!/bin/bash

. ~/bin/functions
is_installed openssl

DIGEST="sha1"
RULER=0
DASH_N=""
while getopts 'mrn' OPTION
do
  case $OPTION in
    m) DIGEST="md5";;
    r) RULER=1;;
    n) DASH_N="-n";;
    ?) printf "usage: %s [ -m ] [ -r ]\n" $( basename $0 ) >&2
       exit 2
       ;;
  esac
done
shift $(($OPTIND - 1))

if [ ! -z $DASH_N ]; then
    RULER=0
fi

DD=$( dd if=/dev/urandom bs=1k count=1 2> /dev/null \
    | openssl dgst -$DIGEST )
echo $DASH_N $DD
if [ $RULER -eq 1 ]; then
    echo '   5|  10|  15|  20|  25|  30|  35|  40|'
fi