Mail Base64 Extraction JPEG

#!/bin/bash
#extracts base64 attachment form mailbox file
#if jpg and decodes it into a file based on
#subject name and date

dir="~/mail/new/*"
for i in `ls $dir`;
do
  ext="$(grep 'Content-Type: image/jpeg;' $i |cut -d\" -f2|cut -d\. -f2)"
  if [ $ext ]
  then
    sub="$(grep "^Subject:" $i|cut -d\: -f2| sed -e 's/^[ \t]*//')"
    file="$(echo "${sub}_$(date +%s).jpg")"
    echo "$file"
    sed '1,/X-Attachment-Id/d' $i |\
      tail -n +2|\
      sed '$ d'|\
      base64 --decode > "$file"
  fi
done