diffdir

#!/bin/bash
# vim:ts=2:sw=2:tw=79
 
set -euo pipefail
shopt -s extglob
shopt -s nocasematch
 
now () {
  if [[ ${BASH_VERSINFO[0]} -ge 4 && ${BASH_VERSINFO[1]} -ge 2 ]] ; then
    printf "%(%s)T" -1
  else
    date +"%s"
  fi
}
 
last_list () {
  local path="$1"
  local latest=""
  local file
  for file in "${path *}"
  tmp="${tmp%%/}/${0##*/}.$dir_md5"
 
  local curr_list="$(now)$(printf "%-.10d" "$$")"
  local last_list="$(last_list "$tmp")"
 
  mkdir -p "$tmp"
  ls -1 "$path" | sort | gzip > "$tmp/$curr_list"
 
  if [[ -z "$last_list" ]] ; then
    diff /dev/null <(zcat "$tmp/$curr_list") | grep -v '^[^<>]'
  else
    diff <(zcat "$last_list") <(zcat "$tmp/$curr_list") | grep -v '^[^<>]'
  fi
}
 
main "$@"