W: Failed to fetch cdrom://Ubuntu 14.04.3 LTS _Trusty Tahr_ - Beta amd64 (20150805)/dists/trusty/main/binary-amd64/Packages Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
W: Failed to fetch cdrom://Ubuntu 14.04.3 LTS _Trusty Tahr_ - Beta amd64 (20150805)/dists/trusty/restricted/binary-amd64/Packages Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
W: Failed to fetch cdrom://Ubuntu 14.04.3 LTS _Trusty Tahr_ - Beta amd64 (20150805)/dists/trusty/main/binary-i386/Packages Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
W: Failed to fetch cdrom://Ubuntu 14.04.3 LTS _Trusty Tahr_ - Beta amd64 (20150805)/dists/trusty/restricted/binary-i386/Packages Please use apt-cdrom to make this CD-ROM recognized by APT. apt-get update cannot be used to add new CD-ROMs
W: Failed to fetch http://packages.mate-desktop.org/repo/ubuntu/dists/precise/main/binary-amd64/Packages 404 Not Found
W: Failed to fetch http://packages.mate-desktop.org/repo/ubuntu/dists/precise/main/binary-i386/Packages 404 Not Found
有时我会得到这个。
W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main amd64 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-amd64_Packages)
W: Duplicate sources.list entry http://dl.google.com/linux/chrome/deb/ stable/main i386 Packages (/var/lib/apt/lists/dl.google.com_linux_chrome_deb_dists_stable_main_binary-i386_Packages)
W: You may want to run apt-get update to correct these problems
我遇到了上述获取问题并尝试进行以下操作。
sudo apt-get -f install && sudo dpkg --configure -a
和
sudo rm /var/lib/apt/lists/* -vf
sudo apt-get update
但还是没有运气，有什么解决办法吗？