I deleted apt on Ubuntu, now what?

Apparently if you do

apt purge ubuntu*

You’ll end up deleting apt. Which is a bummer, because you can’t install anything else, or fix the problem. But not to worry, the resolution is fairly easy.

You can go download the apt deb from Ubuntu’s website and install it with dpkg.

Go to the following link and find the packages for your Ubuntu version

https://packages.ubuntu.com/

You’ll need to show “All packages” at the bottom of the page.

https://packages.ubuntu.com/xenial/allpackages

Download and install ubuntu-keyring, apt-transport-https, and apt packages. Example below

wget security.ubuntu.com/ubuntu/pool/main/a/apt/apt_1.6.6ubuntu0.1_amd64.deb
wget security.ubuntu.com/ubuntu/pool/main/a/apt/apt-transport-https_1.2.29ubuntu0.1_amd64.deb
wget mirrors.kernel.org/ubuntu/pool/main/u/ubuntu-keyring/ubuntu-keyring_2012.05.19_all.deb

Install Packages

sudo dpkg -i ubuntu-keyring_2012.05.19_all.deb
sudo dpkg -i apt-transport-https_1.2.29ubuntu0.1_amd64.deb
sudo dpkg -i apt_1.6.6ubuntu0.1_amd64.deb

Run apt and make sure it is all working

sudo apt update && sudo apt upgrade

unifi depends on mongodb-server (<< 1:3.6.0) | mongodb-10gen (<< 3.6.0) ...

Looks like the issue is that the UniFi server can’t be installed with a version of MongoDB newer then 3.6.0

https://help.ubnt.com/hc/en-us/articles/220066768-UniFi-How-to-Install-Update-via-APT-on-Debian-or-Ubuntu

Fix the issue by installing an older version of MongoDB

wget -qO - https://www.mongodb.org/static/pgp/server-3.4.asc | sudo apt-key add -
echo "deb https://repo.mongodb.org/apt/ubuntu xenial/mongodb-org/3.4 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.4.list
sudo apt-get update

Then install MongoDB with

apt install mongodb-org-server

You may run into issues if you already have a version of Mongo installed. Uninstall it and then rerun the above install command.

Install Microsoft Teams Preview on Linux

Download the correct package for your distribution of Linux from
https://teams.microsoft.com/downloads

You should be able to open the installer and it should install, if not you can run the following commands from a terminal

The install instructions are for Debian/Ubuntu/Linux Mint.

Install using dpkg

sudo dpkg -i Downloads/teams_1.2.00.32451_amd64.deb

Launch Teams by typing

teams

Or you can launch it from your Applications Menu

After Teams is installed and launched, sign in to your Microsoft account.

Install NextCloud on Ubuntu 19.04

Install with snap

sudo snap install nextcloud 

Set user and password for NextCloud

sudo nextcloud.manual-install nextcloudadmin password

Allow https access for firewall

sudo ufw allow 80,443/tcp

For the following steps to work, you’ll need an A record setup on your domain name server to point a domain to your Next Cloud servers public ip address. Change www.example.com in the following steps to the domain name you’ve setup.

View trusted domains

sudo nextcloud.occ config:system:get trusted_domains

Setup new trusted domain. Change www.example.com with your domain.

sudo nextcloud.occ config:system:set trusted_domains 1 --value=www.example.com

Run through Lets Encrypt to setup a SSL certificate.

sudo nextcloud.enable-https lets-encrypt

Should be able to access NextCloud from a web browser www.example.com

Extra info
https://www.digitalocean.com/community/tutorials/how-to-install-and-configure-nextcloud-on-ubuntu-18-04

Set static ip address in Ubuntu 19.04

The network configuration settings for the server edition of Ubuntu are now stored in the following location. Create the file if it does not exist.

sudo vi /etc/netplan/01-network-manager-all.yaml

Add or edit the config file to the following. Change eno1 to your interface name and the address and gateway to the appropriate IP’s

For more information, see netplan(5).
 network:
   version: 2
   renderer: networkd
   ethernets:
     eno1:
      dhcp4: no
      addresses: [192.168.200.24/24]
      gateway: 192.168.200.1
      nameservers:
        addresses: [8.8.8.8,8.8.4.4]

Now apply the changes with the following command.

sudo netplan apply

Verify Ubuntu iso on Windows

On Windows you can use the CertUtil utility to verify an iso image.

First, you’ll need the checksum of the iso. Should be on the page where you downloaded the iso. More info about that here.

Next generate the hash by running the following in a command prompt. Replace the path and ISO name with the one you downloaded

certutil -hashfile Downloads\ubuntu-19.04-live-server-amd64.iso sha256

Example output

SHA256 hash of Downloads\ubuntu-19.04-live-server-amd64.iso:
25d483341ccd0d522a6660b00db933787c86c47b42f1845bcf997127f4b61e9d
CertUtil: -hashfile command completed successfully.

Compare the output with the checksum. If they are the same, you should be good to go.