Mail2sh makes it possible to carry out shell commands by email. Email is sent to a particular user on your host and the commands will be carried out if the user and password given matches ones in /etc/passwd. Commands are executed with the user's privileges, and combined with a PGP module ensures a certain level of security for use. Note that the system is not natively encrypted, so use of an encryption mechanism is highly recommended for security reasons.
This shell script will extract all headers and bodies of a MIME email message recursively into a directory tree. It will also do the reverse operation, walking through a directory tree and regenerating a MIME email message. This script allows you to edit, delete, and add email message components as if they were files.