# cat /etc/apt/sources.list
# deb cdrom:[Ubuntu-Server 14.04 LTS _Trusty Tahr_ - Release amd64 (20140416.2)]/ trusty restricted main
deb http://security.ubuntu.com/ubuntu trusty-security universe main multiverse restricted
# deb-src http://archive.canonical.com/ubuntu trusty partner
deb http://us.archive.ubuntu.com/ubuntu trusty restricted universe main multiverse
# deb http://extras.ubuntu.com/ubuntu trusty main
# deb-src http://extras.ubuntu.com/ubuntu trusty main
deb-src http://security.ubuntu.com/ubuntu trusty-security universe main multiverse restricted
# deb http://archive.canonical.com/ubuntu trusty partner
deb mirror://mirrors.ubuntu.com/mirrors.txt trusty-backports restricted universe main multiverse
deb-src http://us.archive.ubuntu.com/ubuntu trusty restricted universe main multiverse
deb mirror://mirrors.ubuntu.com/mirrors.txt trusty restricted main multiverse universe