How can I replace Snap application such as Gnome Calculator with a deb?

Snap packages installed by default in Ubuntu 18.04 LTS are:

• gnome-calculator
• gnome-characters
• gnome-logs
• gnome-system-monitor

Which can be found using the command sudo snap list. To remove default Snap apps use:

sudo snap remove gnome-calculator gnome-characters gnome-logs gnome-system-monitor

Then install their .deb counterparts with:

sudo apt install gnome-calculator gnome-characters gnome-logs gnome-system-monitor

Additionaly, you can uninstall the whole Snapd ecosystem from your computer with:

sudo apt purge snapd squashfs-tools gnome-software-plugin-snap

This answer is for Ubuntu 18.04 LTS. The version 16.04 LTS came with the deb version by default and not the snap version.

The Graphical way

Click on the Ubuntu Software icon and search for gnome-calc:

To verify which is which, click on each one in turn. When you click on the installed version and scroll down you will see:

Note the Snap Store at the bottom

When you click on the second one and scroll down you will see:

Now you can click on Remove button for the snap version to remove it. Similarly click on the Install button to install the deb version. In both cases you will be asked for the password.

The command line way

Open a terminal by entering Ctrl+Alt+T and enter to following to remove the snap version:

sudo snap remove gnome-calculator

and enter the following to install the deb version:

sudo apt install gnome-calculator

You will be prompted for your password. Unlike the graphical method, you will not see any ***** and the cursor will not move when you type your password. This is normal.

Hope this helps

This will remove all snap packages except core and core18 in one command

sudo snap remove `sudo snap list | cut -d " " -f 1 | tail -n 2 | grep -v 'core' | tr '\n' ' '`

To finish purging do like mentioned above:

sudo apt -y purge snapd gnome-software-plugin-snap

I'm assuming you might seen squashfs-tools in another package