Please, I will like to know where exactly I can download the source code of Ubuntu 18.04 LTS. Can anyone help? Thanks.

I'm was trying to add Ubuntu repository on Debian, but get an error:Err:11 https://mirrors.ustc.edu.cn/ubuntu focal InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 3B4FE6ACC0B21F32 NO_PUBKEY 871920D1991BC93C How to fix it?

My operating system is Ubuntu Bionic beaver. I have written a systemd serivce unit: /etc/systemd/user# ll total 20 drwxrw-r-x 2 rock64 rock64 4096 Nov 23 15:06 ./ drwxr-xr-x 5 root root 4096 Nov 20 07:21 ../ -rw-r--r-- 1 rock64 rock64 74 Nov 23 14:30 photon_uploader.env -rwxr-xr-x 1 rock6...

I followed step-install-gitlab tuorial. The contents of my yml file: web: image: 'gitlab/gitlab-ee:latest' container_name: 'gitlab-howtoforge-tutorial' restart: always hostname: 'miki' environment: GITLAB_OMNIBUS_CONFIG: | external_url 'miki' gitlab_rails['smtp_enable']...

I have accidentally run command pkill -U root. I was in root user.. now I am not able to access through ssh from my local system but I can access my server's terminal on my browser from my digitl ocean account.