Foreword: When I installed the ubuntu16.04 operating system, it was very slow to execute apt-get update. Later, I found this method on the Internet.
1. Open the terminal and enter the directory:
cd /etc/apt
2. Backup the original source file:
sudo cp sources.list sources.list.bak
3. Modify the source.list file, clear the contents, and copy the following contents into it:
sudo vim /etc/apt/sources.list
#After opening the file, enter the following command in vim command mode (default) and press Enter to clear the file content:
:%d
#Copy the content below and save and exit
# deb cdrom:[Ubuntu 16.04 LTS _Xenial Xerus_ - Release amd64 (20160420.1)]/ xenial main restricted
deb-src https://archive.ubuntu.com/ubuntu xenial main restricted #Added by software-properties
deb https://mirrors.aliyun.com/ubuntu/ xenial main restricted
deb-src https://mirrors.aliyun.com/ubuntu/ xenial main restricted multiverse universe #Added by software-properties
deb https://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted
deb-src https://mirrors.aliyun.com/ubuntu/ xenial-updates main restricted multiverse universe #Added by software-properties
deb https://mirrors.aliyun.com/ubuntu/ xenial universe
deb https://mirrors.aliyun.com/ubuntu/ xenial-updates universe
deb https://mirrors.aliyun.com/ubuntu/ xenial multiverse
deb https://mirrors.aliyun.com/ubuntu/ xenial-updates multiverse
deb https://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src https://mirrors.aliyun.com/ubuntu/ xenial-backports main restricted universe multiverse #Added by software-properties
deb https://archive.canonical.com/ubuntu xenial partner
deb-src https://archive.canonical.com/ubuntu xenial partner
deb https://mirrors.aliyun.com/ubuntu/ xenial-security main restricted
deb-src https://mirrors.aliyun.com/ubuntu/ xenial-security main restricted multiverse universe #Added by software-properties
deb https://mirrors.aliyun.com/ubuntu/ xenial-security universe
deb https://mirrors.aliyun.com/ubuntu/ xenial-security multiverse