目录:
/etc/apt/sources.list
操作：
mv /etc/apt/sources.list /etc/apt/sources.list.bak_curday
vim /etc/apt/sources.list
更换成清华源：
复制进去
1 # deb cdrom:[Ubuntu 20.04 LTS _Focal Fossa_ - Release amd64 (20200423)]/ focal main restricted 2 3 # See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to 4 # newer versions of the distribution. 5 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal main restricted 6 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal main restricted 7 8 ## Major bug fix updates produced after the final release of the 9 ## distribution. 10 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates main restricted 11 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal-updates main restricted 12 13 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 14 ## team. Also, please note that software in universe WILL NOT receive any 15 ## review or updates from the Ubuntu security team. 16 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal universe 17 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal universe 18 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates universe 19 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal-updates universe 20 21 ## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 22 ## team, and may not be under a free licence. Please satisfy yourself as to 23 ## your rights to use the software. Also, please note that software in 24 ## multiverse WILL NOT receive any review or updates from the Ubuntu 25 ## security team. 26 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal multiverse 27 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal multiverse 28 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-updates multiverse 29 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal-updates multiverse 30 31 ## N.B. software from this repository may not have been tested as 32 ## extensively as that contained in the main release, although it includes 33 ## newer versions of some applications which may provide useful features. 34 ## Also, please note that software in backports WILL NOT receive any review 35 ## or updates from the Ubuntu security team. 36 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-backports main restricted universe multiverse 37 # deb-src http://us.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse 38 39 ## Uncomment the following two lines to add software from Canonical's 40 ## 'partner' repository. 41 ## This software is not part of Ubuntu, but is offered by Canonical and the 42 ## respective vendors as a service to Ubuntu users. 43 # deb http://archive.canonical.com/ubuntu focal partner 44 # deb-src http://archive.canonical.com/ubuntu focal partner 45 46 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security main restricted 47 # deb-src http://security.ubuntu.com/ubuntu focal-security main restricted 48 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security universe 49 # deb-src http://security.ubuntu.com/ubuntu focal-security universe 50 deb http://mirrors.tuna.tsinghua.edu.cn/ubuntu/ focal-security multiverse 51 # deb-src http://security.ubuntu.com/ubuntu focal-security multiverse 52 53 # This system was installed using small removable media 54 # (e.g. netinst, live or single CD). The matching "deb cdrom" 55 # entries were disabled at the end of the installation process. 56 # For information about how to configure apt package sources, 57 # see the sources.list(5) manual.