Commands and aliases
When installing a snap, you’re often installing an application. If an application uses a GUI, it will be integrated into your desktop environment and it can be launched just like any other GUI application.
But applications installed from a snap can also be run from the command line, regardless of whether they’re GUI-based or terminal-based.
The following sections describe how to work with such snap applications.
As covered in Getting started, a snap’s installed application(s) can be found under
/snap/bin, and subsequently, often added to $PATH. This makes commands directly accessible from the command line.
If executing a command directly doesn’t work, try prefixing it with the /snap/bin path:
/snap/bin to your default $PATH makes running snaps that don’t automatically add themselves more convenient.
The output to
snap info lists the applications a snap makes available beneath the commands: section:
$ snap info vlc name: vlc summary: The ultimate media player (...) commands: - vlc (...)
To avoid the potential conflict of snaps exposing applications with the same name, every snap has a namespace reserved for itself. The namespace uses the following syntax:
<snap name>.<application name>
The first option is used automatically when the exposed application name matches the name of the snap, such as with vlc. The second option is used for every other case.
The namespace syntax (see above) is effective at preventing conflicts, but it’s not ideal when applications have well known names that third-party scripts depend upon. This is where aliases are useful.
For example, the LXD container manager snap exposes the application as lxd. However, many third-party scripts depend on this being lxc. To solve this issue, the LXD snap creates an alias for lxc.
Aliases can be viewed with the
snap alias command:
$ snap aliases lxd Command Alias Notes lxd.lxc lxc -
Unlike applications that use a snap’s namespace, there is no guarantee that an alias is going to be unique. For this reason, aliases can be easily disabled and re-enabled with the
$ sudo snap unalias lxd Removed: - lxd.lxc as lxc $ sudo snap prefer lxd Added: - lxd.lxc as lxc
The prefer command enables all aliases for a given snap in preference to conflicting aliases from other snaps. This allows you to switch application preference between alternative options provided by other snaps.
As there is no guarantee that an aliases is going to be unique, and potential conflicts create a minor inconvenience, a snap’s default aliases are only enabled after a simple public review process.
The same review process also ensures that any default commands exposed by a snap are either named after the snap or, when different, reviewed to ensure the alias is relevant within the context of the application. This helps maintain a sane shared namespace for everyone.
If you want an alias enabled for your snap, please open a small forum topic in the store requests category with the details.
Snap’s aliasing system supports the creation of arbitrary custom aliases defined for the local system. This allows applications to be exposed under any name that is convenient locally.
For example, the following exposes a new command under
/snap/bin to support calling the
vlc application as
$ sudo snap alias vlc my-vlc Added: - vlc as my-vlc $ snap aliases vlc Command Alias Notes vlc my-vlc manual
When a manual alias is set, the original application name will continue to function.
Removing a manually created aliases is also straightforward:
$ sudo snap unalias my-vlc Removed: - vlc as my-vlc
Daemons and services
Some applications may also be exposed as daemons or services which run in the background automatically when the snap is installed.
See Service management for more details.
Last updated 1 year, 3 months ago.