问题：

sudo apt install jupyter-notebook安装notebook失败E: Aborting install.

~/jie/mywork/PointNetCFD$ sudo apt install jupyter-notebook --fix-missing
Reading package lists... Done
Building dependency tree       
Reading state information... Done
……
After this operation, 174 MB of additional disk space will be used.
Do you want to continue? [Y/n] y
Ign:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates/main amd64 python3-jinja2 all 2.10.1-2ubuntu0.2
Ign:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates/main amd64 python3-jinja2 all 2.10.1-2ubuntu0.2
Ign:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates/main amd64 python3-jinja2 all 2.10.1-2ubuntu0.2
Err:1 https://mirrors.tuna.tsinghua.edu.cn/ubuntu focal-updates/main amd64 python3-jinja2 all 2.10.1-2ubuntu0.2
  404  Not Found [IP: 101.6.15.130 443]
Unable to correct missing packages.
E: Failed to fetch https://mirrors.tuna.tsinghua.edu.cn/ubuntu/pool/main/j/jinja2/python3-jinja2_2.10.1-2ubuntu0.2_all.deb  404  Not Found [IP: 101.6.15.130 443]
E: Aborting install.

解决方法：

使用下面这个命令

conda install notebook

成功安装

然后再输入

jupyter-notebook

即可打开notebook,如下图所示