Decompress an MD5 checksum into the file it represents :-)

md5decompress.sh

#!/bin/bash
#
# "Decompress" an MD5 sum into the file it represents.
# This was created following a tongue-in-cheek challenge by Tom Limoncelli.
# https://twitter.com/yesthattom/status/716670884698828800
#
# Try md5decompress.sh c1a5298f939e87e8f962a5edfc206918
#

if [ "x$1" = x ] ; then
  echo "Usage: $0 MD5sum" 1>&2
  exit 1
fi

echo 0 > num
while : ; do
  { echo 'obase = 256' ; cat num ; } |
    bc |
    sed 's/ 0*\([1-9]\)/ \1/g;s/\\//;s/^  *//;s/  */\n/g' |
    while read b ; do
      printf %b '\0'$(printf %o $b)
    done >try
    if [ "$1  -" = "$(md5sum <try)" ] ; then
      cat try
      exit 0
    fi
  echo $(cat num) + 1 | bc >next
  mv next num
done