Install OMV3 on Debian Jessie

cat <<EOF >> /etc/apt/sources.list.d/openmediavault.list
deb http://packages.openmediavault.org/public erasmus main
# deb http://downloads.sourceforge.net/project/openmediavault/packages erasmus main
## Uncomment the following line to add software from the proposed repository.
# deb http://packages.openmediavault.org/public erasmus-proposed main
# deb http://downloads.sourceforge.net/project/openmediavault/packages erasmus-proposed main
## This software is not part of OpenMediaVault, but is offered by third-party
## developers as a service to OpenMediaVault users.
# deb http://packages.openmediavault.org/public erasmus partner
# deb http://downloads.sourceforge.net/project/openmediavault/packages erasmus partner
EOF

export LANG=C
export DEBIAN_FRONTEND=noninteractive
export APT_LISTCHANGES_FRONTEND=none
apt-get update
apt-get --allow-unauthenticated install openmediavault-keyring
apt-get update
apt-get --yes --force-yes --auto-remove --show-upgraded \
	--no-install-recommends \
	--option Dpkg::Options::="--force-confdef" \
	--option DPkg::Options::="--force-confold" \
	install postfix openmediavault


# Initialize the system and database.
omv-initsystem