passgen

#!/bin/sh
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
#
# Copyright 2021 Jeremy Brubaker <jbru362@gmail.com>
#
# abstract: generate a password as in XKCD #936

# Process options {
print_help() (
    cat <<EOF
Usage: $0 [OPTION]
Generate an xkcd-936 inspired passphrase

 -f            path to wordlist (default: \$HOME/share/dict/password_words)
 -n            number of words to generate (default: 4)
 -d            word separator (default: none)
 -h            display this help
 -v            display version
EOF
) >&2

print_version() (
    cat <<EOF
$0 1.0
Copyright (C) 2021 Jeremy Brubaker
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Jeremy Brubaker
EOF
) >&2

wordlist="$HOME/share/dict/password_words"
numwords=4
separator=''

while getopts "f:n:d:hv" opt; do
    case $opt in
        f) wordlist="$OPTARG" ;;
        n) numwords="$OPTARG";;
        d) separator="$OPTARG";;
        h) print_help; exit ;;
        v) print_version; exit ;;
        *) print_help; exit ;;
    esac
done
# }

awk 'length <= 5 && length >=3' "$wordlist" \
    | shuf -n"$numwords" | paste -sd "$separator"