Echo can interpret operand as an option and checking every variable to
be echoed is troublesome while with printf, if the format specifier is
present before the operand, printing as string can be enforced.
Split-mail allows to separate the receving, reading/composing and
sending of mails to separate qubes, while having the reading/composing
qube offline and a manual step necessary to authorize mails to be sent
form the sender qube.
