Table of Contents
Why “Universal” Package Formats Exist
Traditional package managers like APT, DNF, and Pacman are tightly integrated with a distribution. Snap, Flatpak, and AppImage aim to:
- Work across multiple distributions.
- Bundle most dependencies with the application.
- Allow newer app versions than what your distro ships.
- Make installation and updates simpler for end users.
They achieve this in different ways, with different trade‑offs.
Snap
Snap is developed by Canonical (the company behind Ubuntu).
Key Characteristics
- Uses a central store: the Snap Store.
- Applications are packaged as
snapfiles. - Strong sandboxing using AppArmor, cgroups, namespaces.
- Automatic background updates.
- Mounts applications as compressed
squashfsimages.
Basic Snap Commands
On Ubuntu, Snap is usually installed by default. On other distros, you may need to install it first from the official Snapcraft site or your distro’s repos.
Common commands:
# Search for an application
snap search <name>
# Install a snap (e.g. VLC)
sudo snap install vlc
# Install a specific channel (e.g. --edge, --beta)
sudo snap install vlc --edge
# List installed snaps
snap list
# Update all snaps
sudo snap refresh
# Update a specific snap
sudo snap refresh vlc
# Remove a snap
sudo snap remove vlc
# Show detailed info about a snap
snap info vlc
Snap applications typically install under /snap and are run via wrappers usually placed in /snap/bin (which is added to your PATH).
Confinement Modes and Permissions
Snap’s sandboxing is called “confinement”:
- strict: default, limited access to system; needs explicit interfaces.
- classic: almost full system access, more like a traditional package (used for tools like
code,go, etc.). - devmode: for development/testing, not used for normal users.
Snaps connect to “interfaces” to access hardware or data (e.g. camera, network, removable-media):
# List interfaces for an installed snap
snap connections vlc
# Manually connect an interface (example)
sudo snap connect vlc:removable-mediaPros and Cons of Snap
Pros
- Automatic and transactional updates.
- Same package works on many distros.
- Strong sandboxing for most apps.
- Easy to install GUI and CLI apps from the same store.
Cons
- Start‑up time can be slower (mounted compressed filesystem).
- Heavier disk usage than native packages.
- Centralized infrastructure (Snap Store is controlled by Canonical).
- Not all distributions integrate Snap by default; some discourage it.
Flatpak
Flatpak targets graphical desktop applications and is widely adopted by desktop‑oriented distributions.
Key Characteristics
- Focus on GUI desktop apps (though CLI apps are possible).
- Uses runtimes (shared platforms like
org.freedesktop.Platform) plus app layers. - Sandboxed using namespaces, seccomp, and optional portals.
- Uses remotes (repositories), with Flathub as the most common one.
- Can install per‑user (no root) or system‑wide.
Setting Up Flatpak (Example: Debian/Ubuntu)
Typically:
sudo apt install flatpak
# On many desktop environments:
sudo apt install gnome-software-plugin-flatpak
# Add the main Flathub remote (one-time setup)
sudo flatpak remote-add --if-not-exists flathub \
https://flathub.org/repo/flathub.flatpakrepoYour distro may have its own Flatpak remote preconfigured; check the documentation.
Basic Flatpak Commands
# Search for an application
flatpak search <name>
# Install from Flathub (fully qualified ID recommended)
flatpak install flathub org.videolan.VLC
# List installed applications
flatpak list
# Run an application
flatpak run org.videolan.VLC
# Update all Flatpaks
flatpak update
# Remove an application
flatpak uninstall org.videolan.VLC
# Show more info
flatpak info org.videolan.VLC
Flatpak IDs are typically reverse‑DNS style: org.gnome.Terminal, com.spotify.Client, etc.
Permissions and Sandboxing
Flatpak apps are sandboxed. By default they can only access:
- Their own files in a private directory (usually under
~/.var/app/…). - Limited system resources, unless granted.
You can inspect or change permissions using tools like:
# Show runtime and permissions
flatpak info --show-permissions org.videolan.VLC
On many desktops, a GUI tool like Flatseal (installed as a Flatpak itself) provides an easy way to tweak these.
Pros and Cons of Flatpak
Pros
- Good desktop integration across many distributions.
- Per‑user installs without root.
- Runtimes reduce duplication between apps.
- Strong sandboxing and permission system.
Cons
- Large runtimes can still consume significant disk space.
- Best suited for desktop GUI apps, less ideal for small CLI utilities.
- Managing multiple remotes and runtimes can be confusing at first.
AppImage
AppImage is the simplest of the three in terms of system integration.
Key Characteristics
- Single self‑contained executable file (an
AppImage). - No central package manager or service is required.
- No installation in the traditional sense; you just download and run.
- No built‑in sandboxing (apps run with normal user permissions).
- Very portable across distributions when dependencies are bundled.
Using an AppImage
Typical usage looks like this:
- Download an
.AppImagefile from the project’s website or a catalog site. - Make it executable.
- Run it.
Example:
# Move into your Downloads or wherever the file is
cd ~/Downloads
# Make the AppImage executable
chmod +x MyApp-1.2.3-x86_64.AppImage
# Run it
./MyApp-1.2.3-x86_64.AppImage
You can keep the file anywhere (e.g. ~/Applications) and create a .desktop launcher manually or with helper tools if you want menu integration.
Pros and Cons of AppImage
Pros
- Very simple concept: one file = one app.
- No root needed, no system‑wide installs.
- Easy to carry on USB or share between machines.
- Doesn’t touch system libraries or package database.
Cons
- No automatic updates unless the app provides its own mechanism.
- No unified permission model or sandbox by default.
- Each AppImage may bundle its own libraries, increasing duplication.
- Integration into menus and desktop environment may require extra steps.
Comparing Snap, Flatpak, and AppImage
Target Use Cases
- Snap
- Desktop and server apps.
- Good for tools, services, and apps that benefit from automatic updates.
- Heavier system integration and central store.
- Flatpak
- Primarily desktop GUI applications.
- Popular on distributions like Fedora, Linux Mint, Manjaro.
- Commonly used with Flathub.
- AppImage
- Stand‑alone apps, portable and simple.
- Good when you want a single binary and full control over updates.
Sandboxing and Security
- Snap: Strong confinement for most apps; uses system security features and interfaces.
- Flatpak: Strong sandboxing with fine‑grained permissions, integrates with portals for safe file access.
- AppImage: No sandboxing by default; behaves like running any other user‑level binary.
Updates
- Snap: Automatic, scheduled updates with rollback support.
- Flatpak: Updates via
flatpak update(can be automated by desktop tools). - AppImage: Depends on the app; often you manually download a new file.
Disk Space and Performance
- Snap: Multiple versions plus compression can consume more disk; startup can be slower.
- Flatpak: Shared runtimes reduce duplication, but runtimes themselves are large.
- AppImage: Each file is self‑contained; no shared runtimes, but easy to manage individually.
When to Use Which (Beginner Guidance)
As a beginner, consider:
- Your distribution:
- Ubuntu and derivatives: Snap is integrated; Flatpak can be added.
- Fedora, Linux Mint, Manjaro: Flatpak is usually the preferred “universal” format.
- Your needs:
- Need the latest desktop app not in your repos? Try Flatpak (Flathub) or Snap.
- Want a self‑contained portable binary with minimal system changes? Use AppImage.
- Running server tools and want automatic updates and isolation? Snap is often more common than Flatpak or AppImage.
Always prefer your distribution’s normal package manager first for core system components, then look to Snap, Flatpak, or AppImage if the app/version you need is not available there.