How to completely remove snap and replace with flatpak?

Question

I want to remove every piece of existing software/package on Ubuntu related to snap and replace with flatpak.

How to completely remove snap in Ubuntu 19.04 and replace with flatpak without crashing or messing my existing system?

Answer 1

You can do this manually or with unsnap (more at the end).

Why?

Here is a nice article. Basically, snap installs only from a proprietary Canonical repository, you don't have the freedom to change that. Also, installs files to nonstandard locations.

On the other hand, flatpak has its detractors too:

• flatkill.org. Here a response.
• Flatpak Is Not the Future. Here a response.

Remove Snap

Probably for people who just hope Canonical give up with Snap/snapcraft (at least for Desktop):

# Stop snapd services
sudo systemctl stop snapd && sudo systemctl disable snapd
Purge snapd
sudo apt purge -y snapd gnome-software-plugin-snap
Remove no longer needed folders
rm -rf ~/snap
sudo rm -rf /snap /var/snap /var/lib/snapd /var/cache/snapd /usr/lib/snapd
Prevent reinstall
sudo apt-mark hold snap snapd
cat <<EOF | sudo tee /etc/apt/preferences.d/snapd
Package: snapd
Pin: origin *
Pin-Priority: -1
EOF

If you are unsure about removing snap completely, you can at least reduce it at its minimum: remove snap-store, remove snap plugin from GNOME Software; and of course remove any snap also available as flatpak, like Ungoogled Chromium ¹.
Worth to mention that "it's possible to remove all the snaps, and remove snapd... the desktop will function fine" (from a former snap developer; see unsnap below). gnome-... snaps are just backends for GTK snap apps.

sudo snap remove snap-store  # And anything you don't use of  snap list
sudo apt purge gnome-software-plugin-snap
sudo apt install gnome-software-plugin-flatpak

Sources:

• How to uninstall snap?
• How to remove snap completely without losing the Chromium browser?
• Completely Remove Snap from Ubuntu Linux [Tutorial]

Remove snap also from command-not-found

Is also possible to change command-not-found behavior to stop suggesting installing snap packages (Command 'something' not found, but can be installed with:), tuning advice method from CommandNotFound class on /usr/lib/python3/dist-packages/CommandNotFound/CommandNotFound.py (/usr/share/doc/command-not-found/README.md is obsolete). Near the end (line 365) add snaps, mispell_snaps = ['',''] to force an empty result.

         packages = self.get_packages(command)
         snaps, mispell_snaps = self.get_snaps(command)
         snaps, mispell_snaps = ['','']
         logging.debug("got debs: %s snaps: %s" % (packages, snaps))

This applies to bash. On zsh /usr/lib/command-not-found seeems to be used.

Install Flatpak

1. Install Flatpak on Ubuntu 18.10 or later (check here for older versions).

   sudo apt install flatpak
   

2. Install the Software Flatpak plugin: The Flatpak plugin for the Software app makes it possible to install apps without needing the command line. To install, run:

   sudo apt install gnome-software-plugin-flatpak
   

3. Add the Flathub repository: Flathub is the best place to get Flatpak apps. To enable it, run:

   flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo
   

   Add --user if you'll install per-user apps.

4. Restart your system (reboot).

To adjust flatpak permissions check Flatseal (flatpak install flatseal).

Common commands

Using flatpak install/uninstall nameOfTheApp usually is enough. It will run a fuzzy search and suggest alternatives.

• flatpak run name: Run an installed application.

• flatpak install remote name: Install an application from a remote source. --user will install per-user. Examples:

  $ flatpak install flathub org.gnome.gedit
  $ flatpak --user install flathub org.gnome.gedit//3.30
  $ flatpak --user install https://flathub.org/repo/appstream/org.gnome.gedit.flatpakref
  

• flatpak list: List all installed applications and runtimes.

• flatpak update: Update all installed applications and runtimes.

• flatpak remove name: Remove an installed application. --unused also remove unused refs on the system.

• flatpak info name: Show information about an installed application.

unsnap

Ex snap developer Alan Pope had developed unsnap (currently on pre-alpha status) to Quickly migrate from using snap packages to flatpaks:

Quickly and easily migrate from using snap for applications to flatpak. unsnap runs as a two-stage process. unsnap itself generates the scripts to do the actual migration. This enables users to view and/or edit the scripts prior to execution to validate or tweak them.

pop-transition is a similar project.

Related

• Privacy Guides: Linux Overview
• Other apps technologies and sources
  • AppImage/AppImageHub
  • Homebrew: The missing package manager for macOS (or Linux).
  • PyPI: The Python Package Index (PyPI) is a repository of software for the Python programming language. pip: A tool for installing and managing Python packages.

Answer 2

sudo apt purge snapd gnome-software-plugin-snap 

Thanks to doug. It feels so clean now, all snap removed.