flatpak 和 snap 是目前轻量级 Linux 应用程序虚拟化的两个主流方案。
PS: 还有一个存在很久的方案: AppImage，一直不温不火的存在着。
所谓 Application Virtualization，就是给应用程序弄一个标准的执行环境，屏蔽下面各种发行版的差异。他们采用的技术或许有相通的点，也可能完全不一样，我也没有深入研究。
我感觉这是大趋势，最后可能会出现一个像类似 Google Play、 Apple Store, Windows Store 这种东西，统一 Linux 应用分发市场。当然，这会涉及了很大的利益，谁都想能获得这个市场的主导权，所以这里面的斗争可能很难出最后结果。
flatpak 来自红帽，snap 来自 Ubuntu，两种方式目前都没有能够有足够的话语权（可能他们都不能走到最后，被别的新方案淘汰）。我比较看好 flatpak，毕竟红帽的技术实力在那里，大部分技术都是红帽在推动，相比较而言，Ubuntu 多次想把自己的技术推广出来都是失败。
可能是因为我用的 Ubuntu 的缘故（默认就有一些应用是 snap 安装），感觉好像 snap 出镜率比较高，但我有几次使用 snap 的经历，每次都不是很舒服，最后都是狼狈的回退（和我尝试过 homedrew 体验一样糟糕）。flatpak 我这还是第一次使用。因为今天看到新闻说 GNOME 推出了
关于 Flatpak
2016 年刚退出的时候叫做 xdg-app（XDG 是 X Desktop Group, 代表 Linux 桌面），旋即改名为 flatpak。
- 运行时 Runtimes: 屏蔽不同发行版的差异
- 库 Bundled libraries
- 沙箱 Sandboxes: 需要访问外部资源必须显式申明并得到授权，对外暴露资源叫做 “导出”
- 门户 Portals: 沙箱对外部资源访问的一种机制，可能类似浏览器向 JS 提供的 API
- 仓库 Repositories: 与更新源的概念类似
每个 App 是运行在对应的 Runtime 基础之上，而 App 和 Runtime 都有捆绑其所需要的一堆库。
相比较之下，传统的 Linux 应用直接依赖底层操作系统环境（没有运行时概念），然后是和其他的应用共用依赖库的（不同应用容易有依赖冲突）。
使用
flatpak --help
Usage:
flatpak [OPTION…] COMMAND
Builtin Commands:
Manage installed applications and runtimes
install Install an application or runtime
update Update an installed application or runtime
uninstall Uninstall an installed application or runtime
mask Mask out updates and automatic installation
pin Pin a runtime to prevent automatic removal
list List installed apps and/or runtimes
info Show info for installed app or runtime
history Show history
config Configure flatpak
repair Repair flatpak installation
create-usb Put applications or runtimes onto removable media
Finding applications and runtimes
search Search for remote apps/runtimes
Running applications
run Run an application
override Override permissions for an application
make-current Specify default version to run
enter Enter the namespace of a running application
ps Enumerate running applications
kill Stop a running application
Manage file access
documents List exported files
document-export Grant an application access to a specific file
document-unexport Revoke access to a specific file
document-info Show information about a specific file
Manage dynamic permissions
permissions List permissions
permission-remove Remove item from permission store
permission-set Set permissions
permission-show Show app permissions
permission-reset Reset app permissions
Manage remote repositories
remotes List all configured remotes
remote-add Add a new remote repository (by URL)
remote-modify Modify properties of a configured remote
remote-delete Delete a configured remote
remote-ls List contents of a configured remote
remote-info Show information about a remote app or runtime
Build applications
build-init Initialize a directory for building
build Run a build command inside the build dir
build-finish Finish a build dir for export
build-export Export a build dir to a repository
build-bundle Create a bundle file from a ref in a local repository
build-import-bundle Import a bundle file
build-sign Sign an application or runtime
build-update-repo Update the summary file in a repository
build-commit-from Create new commit based on existing ref
repo Show information about a repo
Help Options:
-h, --help Show help options
Application Options:
--version Print version information and exit
--default-arch Print default arch and exit
--supported-arches Print supported arches and exit
--gl-drivers Print active gl drivers and exit
--installations Print paths for system installations and exit
--print-updated-env Print the updated environment needed to run flatpaks
--print-system-only Only include the system installation with --print-updated-env
-v, --verbose Show debug information, -vv for more detail
--ostree-verbose Show OSTree debug information
flatpak search wike
Name Description Application ID Version Branch Remotes
Wike Wikipedia Reader com.github.hugolabe.Wike 1.5.4 stable flathub
Outwiker Personal wiki and outliner. net.jenyay.Outwiker 3.1.0.892 stable flathub
flatpak install wike
Found similar ref(s) for ‘wike’ in remote ‘flathub’ (system).
Use this remote? [Y/n]: y
Similar refs found for ‘wike’ in remote ‘flathub’ (system):
1) app/com.github.hugolabe.Wike/x86_64/stable
2) app/net.jenyay.Outwiker/x86_64/stable
Which do you want to use (0 to abort)? [0-2]: 1
...
flatpak list
Name Application ID Version Branch Installation
Wike com.github.hugolabe.Wike 1.5.4 stable system
Mesa org.freedesktop.Platform.GL.default 21.1.4 20.08 system
nvidia-470-57-02 org.freedesktop.Platform.GL.nvidia-470-57-02 1.4 system
Intel org.freedesktop.Platform.VAAPI.Intel 20.08 system
openh264 org.freedesktop.Platform.openh264 2.1.0 2.0 system
GNOME Application Platform version 40 org.gnome.Platform 40 system
Yaru-dark Gtk Theme org.gtk.Gtk3theme.Yaru-dark 3.22 system
flatpak run com.github.hugolabe.Wike
