#!/bin/bash

quelle="$1"
[ -z "${quelle}" ] && quelle=~/.thunderbird/xguz6fup.default/ImapMail/imap.gmx.net/INBOX

grep '^\($\|From\|[-a-zA-Z0-9.]\+: \)' "${quelle}" | \
  grep -vi '^\(X-[-a-zA-Z]\+\|Bounces-to\|Content-Id\|Message-Id\|References\|In-Reply-To\|Return-Path\):' | \
  while read -r s
  do
    [[ "$s" = 'From - '* ]] && \
      sammle=true
    [ -z "$s" ] && \
      sammle=false
    $sammle && \
      echo "$s"
  done | \
  tr ' <>;()":,' '\n' | \
  grep -v '^#' | \
  sed 's|?.*$||; s|\(@.*\)@.*$|\1|' | \
  grep -v '\[[0-9]\+\.' | \
  grep -vi bounce | \
  tr '[]' '\n' | \
  sed 's|^\s\+||; s|\s\+$||' | \
  sed 's@=\(20\|0A\|5F\|3D\)@\n@g' | \
  sed 's@^\(envelope-from\|header\.i\|news\|service\)=@\n@' | \
  sed 's|&gt$||' | \
  tr "'"'%# `|/' '\n' | \
  grep -v '=' | \
  grep '.\+@.\+\..\+' | \
  pv --line-mode | \
  sort -fu | \
  while read -r s
  do
    seq -s' ' 100 | \
      gpg --search-keys "$s"
  done