Script to crack a LUKS partition given a fuzzy passphrase pattern

crack.sh

#!/usr/bin/env bash

set -e

the_pattern=$1
# We need to export because xargs runs in a subshell
export the_file=$2

if [ -z "${the_pattern}" ]; then
  echo pattern missing
  exit 1
fi

if [ -z "${the_file}" ]; then
  echo file missing
  exit 1
fi

crack_maybe=$(cat <<'EOF'
    echo PASS | cryptsetup open --test-passphrase ${the_file}
    rc=$?
    if [ "$rc" -ne "2" ]; then
    echo "return code $rc on input PASS"
    exit 255
    fi
EOF
)

echo "starting..."
stutter ${the_pattern} \
    | parallel --ungroup --block-size 1k --progress --pipe --halt now,fail=1 \
    " xargs -n 1 -I PASS sh -c '$crack_maybe'"
echo "Done."