结果python ––version：
Command 'python' not found, but can be installed with:
sudo apt install python3
sudo apt install python
sudo apt install python-minimal
You also have python3 installed, you can run 'python3' instead.
cat 的结果/etc/apt/sources.list：
# deb cdrom:[Ubuntu 18.04.1 LTS _Bionic Beaver_ - Release amd64 (20180725)]/ bionic main restricted
# See http://help.ubuntu.com/community http://packages.ros.org/ros/ubuntu/y/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb [trusted=yes] http://br.archive.ubuntu.com/ubuntu/ bionic restricted main
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic main restricted
## Major bug fix updates produced after the final release of the
## distribution.
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic-updates main restricted
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://br.archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic universe
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic-updates universe
## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://br.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic multiverse
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic-updates multiverse
## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://br.archive.ubuntu.com/ubuntu/ bionic-backports restricted universe multiverse main
# deb-src http://br.archive.ubuntu.com/ubuntu/ bionic-backports main restricted universe multiverse
## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu bionic partner
# deb-src http://archive.canonical.com/ubuntu bionic partner
deb http://security.ubuntu.com/ubuntu bionic-security restricted main
# deb-src http://security.ubuntu.com/ubuntu bionic-security main restricted
deb http://security.ubuntu.com/ubuntu bionic-security universe
# deb-src http://security.ubuntu.com/ubuntu bionic-security universe
deb http://security.ubuntu.com/ubuntu bionic-security multiverse
deb http://archive.canonical.com/ bionic partner
# deb-src http://archive.canonical.com/ bionic partner
# deb-src http://security.ubuntu.com/ubuntu bionic-security multiverse
deb http://br.archive.ubuntu.com/ubuntu/ bionic-updates main multiverse universe restricted
deb http://my-private-server.test bionic main
# deb-src http://my-private-server.test bionic main
结果sudo apt update：
E: Conflicting values set for option Trusted regarding source http://br.archive.ubuntu.com/ubuntu/ bionic
E: The list of sources cannot be read.
结果/etc/apt/sources.list：
bash: /etc/apt/sources.list: Permission denied
更新
尝试修复该问题后（@PMF 请在此处添加你所做的事情），它仍然不起作用。sources.list现在的第 5 行内容为：
~$ sed -n 5p /etc/apt/sources.list
deb deb [arch=amd64 trusted=yes] http://br.archive.ubuntu.com/ubuntu/ bionic main http://br.archive.ubuntu.com/ubuntu/ bionic restricted main
答案1
您[trusted=yes]在这一行中有以下选项：
deb [trusted=yes] http://br.archive.ubuntu.com/ubuntu/ bionic restricted main
但对于具有相同 URL 的其他行则不然，这就是为什么它说您有冲突的选项。
要修复此问题，请将该选项添加到具有相同 URL 的所有其他行，或者更简单地使用您选择的编辑器将其删除，或者只需运行：
sudo sed -i '/bionic restricted main$/s/^deb \[trusted=yes]/deb/' /etc/apt/sources.list