报错如下：
Ign:1 http://archive.ubuntu.com/ubuntu bionic InRelease
Ign:2 http://security.ubuntu.com/ubuntu bionic-security InRelease
Ign:3 http://archive.ubuntu.com/ubuntu bionic-updates InRelease
Err:4 http://security.ubuntu.com/ubuntu bionic-security Release
SECURITY: URL redirect target contains control characters, rejecting. [IP: 91.189.88.152 80]
Ign:5 http://archive.ubuntu.com/ubuntu bionic-backports InRelease
Err:6 http://archive.ubuntu.com/ubuntu bionic Release
SECURITY: URL redirect target contains control characters, rejecting. [IP: 91.189.88.152 80]
Err:7 http://archive.ubuntu.com/ubuntu bionic-updates Release
SECURITY: URL redirect target contains control characters, rejecting. [IP: 91.189.88.152 80]
Err:8 http://archive.ubuntu.com/ubuntu bionic-backports Release
SECURITY: URL redirect target contains control characters, rejecting. [IP: 91.189.88.142 80]
Reading package lists... Done
E: The repository 'http://security.ubuntu.com/ubuntu bionic-security Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu bionic Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu bionic-updates Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
E: The repository 'http://archive.ubuntu.com/ubuntu bionic-backports Release' does not have a Release file.
N: Updating from such a repository can't be done securely, and is therefore disabled by default.
N: See apt-secure(8) manpage for repository creation and user configuration details.
解决办法：换源
普通用户权限下一定要加sudo，否则没有修改sources.list的权限
将sources.list的文件全部删除，替换成
deb http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-security main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-updates main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-backports main restricted universe multiverse
deb http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
deb-src http://mirrors.aliyun.com/ubuntu/ bionic-proposed main restricted universe multiverse
然后执行sudo apt-get update就不会报错了