У меня была та же проблема. Я пытался помочь себе со стандартными инструментами Unix. Я сделал небольшой скрипт bash, который идеально подходит для моих нужд. Я не программист, программист, возможно, сделает это по-другому. Просто посмотрите и не стесняйтесь изменять/улучшать сценарий. Комментарии приветствуются! (для улучшения моего программирования bash :-)
#!/bin/bash
#Script extracts attachments out of a "ASCII" email file.
# Using grep, head, tail and openssl.
# Start of a attachment looks like this in the file:
#
#--Part_0_1323333549.1457526416376
#Content-Type: application/octet-stream;
# name="testfile.zip"
#Content-Transfer-Encoding: base64
#Content-Disposition: attachment; filename="testfile.zip"
#
#UEsfBBQACAAIAAg4fEYAAAAAAAdAAAAAAAAeAAAAQWJsZWhugW5nZW5fQ0RDXzIwMTUtMDMtMjgu
#...
#...
#
# End of a attachment looks like this:
#AAAAAAAAAEFibGVobnVuZ2VuX0NEQ18yMDE1LTAzLTI3LmNzdlBLBQYAAAAAAQABAEwAAACrTwIA
#AAA=
#
#--Part_0_1323333549.1457526416376
#
timestamp=$(date +20%y-%m-%d_%H-%M-%S)
mailpath=~/mail
mailfile=$mailpath/mails
tmpfile=$mailpath/tmpfile.txt
tmpfile2=$mailpath/tmpfile2.txt
outfile=$mailpath/outfile.txt
# fetchmail (MTA=Mail Tranfer Agent) connects to mail-server and routes mails to procmail (MDA=Mail Delivery Agent)
# Configuration ~/.fetchmailrc und ~/.procmailrc
fetchmail
cp $mailfile $tmpfile
# Get NB of all attachments in one or n emails. Option -c in grep (all emails are in $mailfile resp. $tmpfile!)
# to set loops
nbattach=$(grep -ci 'content-disposition: attachment; filename=' $tmpfile)
i=1
while [ $i -le $nbattach ]
do
echo $i. run
#get filename of 1. attachments in remaining $tmpfile --> option -m 1 in grep!
filename=$(grep -ni 'content-disposition: attachment; filename=' $tmpfile -m 1 | cut -d ';' -f 2 | cut -d '=' -f 2 | sed 's/"//g')
echo filename: $filename
#get startline of 1. attachments in remaining $tmpfile--> option -m 1 in grep
startline=$(grep -ni 'content-transfer-encoding: base64' $tmpfile -m 1 | cut -d : -f 1)
#attachment starts after a blank line
let startline=$startline+1
#keep tail in $tmpfile
tail -n +$startline $tmpfile > $tmpfile2
mv $tmpfile2 $tmpfile
#get endline of the 1. attachment in remaining $tmpfile
#attachment ends with a blank line and a string that begins with '--'
endline=$(grep -n '^--' $tmpfile -m 1 | cut -d ':' -f 1)
let endline=$endline-1
#keep head and decode attachment with base64 via openssl.
head -n $endline $tmpfile > $outfile
openssl enc -d -base64 -in $outfile -out ~/mail/attachments/${timestamp}_${i}_${filename}
# keep tail for further attachemnts
let endline=$endline+2
tail -n +$endline $tmpfile > $tmpfile2
mv $tmpfile2 $tmpfile
let i=$i+1
done
rm $tmpfile $outfile