snap man page

snap — Tool to interact with snaps

Examples (TL;DR)

Synopsis

snap [Options]

Description

The snap command lets you install, configure, refresh and remove snaps. Snaps are packages that work across many different Linux distributions, enabling secure delivery and operation of the latest apps and utilities.

Options

Commands

abort

Abort a pending change

The abort command attempts to abort a change that still has pending tasks.

Usage: snap abort [abort-OPTIONS]

--last

Select last change of given type (install, refresh, remove, try, auto-refresh, etc.). A question mark at the end of the type means to do nothing (instead of returning an error) if no change of the given type is found. Note the question mark could need protecting from the shell.

ack

Add an assertion to the system

The ack command tries to add an assertion to the system assertion database.

The assertion may also be a newer revision of a pre-existing assertion that it will replace.

To succeed the assertion must be valid, its signature verified with a known public key and the assertion consistent with and its prerequisite in the database.

alias

Set up a manual alias

The alias command aliases the given snap application to the given alias.

Once this manual alias is setup the respective application command can be invoked just using the alias.

Usage: snap alias [alias-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

aliases

List aliases in the system

The aliases command lists all aliases available in the system and their status.

$ snap aliases <snap>

Lists only the aliases defined by the specified snap.

An alias noted as undefined means it was explicitly enabled or disabled but is not defined in the current revision of the snap, possibly temporarily (e.g. because of a revert). This can cleared with 'snap alias --reset'.

changes

List system changes

The changes command displays a summary of system changes performed recently.

Usage: snap changes [changes-OPTIONS]

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

check-snapshot

Check a snapshot

The check-snapshot command verifies the user, system and configuration data of the snaps included in the specified snapshot.

The check operation runs the same data integrity verification that is performed when a snapshot is restored.

By default, this command checks all the data in a snapshot. Alternatively, you can specify the data of which snaps to check, or for which users, or a combination of these.

If a snap is included in a check-snapshot operation, excluding its system and configuration data from the check is not currently possible. This restriction may be lifted in the future.

Usage: snap check-snapshot [check-snapshot-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--users

Check data of only specific users (comma-separated) (default: all users)

connect

Connect a plug to a slot

The connect command connects a plug to a slot. It may be called in the following ways:

$ snap connect <snap>:<plug> <snap>:<slot>

Connects the provided plug to the given slot.

$ snap connect <snap>:<plug> <snap>

Connects the specific plug to the only slot in the provided snap that matches the connected interface. If more than one potential slot exists, the command fails.

$ snap connect <snap>:<plug>

Connects the provided plug to the slot in the core snap with a name matching the plug name.

Usage: snap connect [connect-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

connections

List interface connections

The connections command lists connections between plugs and slots in the system.

Unless <snap> is provided, the listing is for connected plugs and slots for all snaps in the system. In this mode, pass --all to also list unconnected plugs and slots.

$ snap connections <snap>

Lists connected and unconnected plugs and slots for the specified snap.

Usage: snap connections [connections-OPTIONS]

--all

Show connected and unconnected plugs and slots

create-cohort

Create cohort keys for a series of snaps

The create-cohort command creates a set of cohort keys for a given set of snaps.

A cohort is a view or snapshot of a snap's "channel map" at a given point in time that fixes the set of revisions for the snap given other constraints (e.g. channel or architecture). The cohort is then identified by an opaque per-snap key that works across systems. Installations or refreshes of the snap using a given cohort key would use a fixed revision for up to 90 days, after which a new set of revisions would be fixed under that same cohort key and a new 90 days window started.

disable

Disable a snap in the system

The disable command disables a snap. The binaries and services of the snap will no longer be available, but all the data is still available and the snap can easily be enabled again.

Usage: snap disable [disable-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

disconnect

Disconnect a plug from a slot

The disconnect command disconnects a plug from a slot. It may be called in the following ways:

$ snap disconnect <snap>:<plug> <snap>:<slot>

Disconnects the specific plug from the specific slot.

$ snap disconnect <snap>:<slot or plug>

Disconnects everything from the provided plug or slot. The snap name may be omitted for the core snap.

Usage: snap disconnect [disconnect-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

download

Download the given snap

The download command downloads the given snap and its supporting assertions to the current directory with .snap and .assert file extensions, respectively.

Usage: snap download [download-OPTIONS]

--channel

Use this channel instead of stable

--edge

Install from the edge channel

--beta

Install from the beta channel

--candidate

Install from the candidate channel

--stable

Install from the stable channel

--revision

Download the given revision of a snap, to which you must have developer access

--basename

Use this basename for the snap and assertion files (defaults to <snap>_<revision>)

--target-directory

Download to this directory (defaults to the current directory)

--cohort

Download from the given cohort

enable

Enable a snap in the system

The enable command enables a snap that was previously disabled.

Usage: snap enable [enable-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

find

Find packages to install

The find command queries the store for available packages in the stable channel.

With the --private flag, which requires the user to be logged-in to the store (see 'snap help login'), it instead searches for private snaps that the user has developer access to, either directly or through the store's collaboration feature.

A green check mark (given color and unicode support) after a publisher name indicates that the publisher has been verified.

Usage: snap find [find-OPTIONS]

Aliases: search
--private

Search private snaps

--narrow

Only search for snaps in “stable”

--section [="show-all-sections-please"] <default: "no-section-specified">

Restrict the search to a given section

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

forget

Delete a snapshot

The forget command deletes a snapshot. This operation can not be undone.

A snapshot contains archives for the user, system and configuration data of each snap included in the snapshot.

By default, this command forgets all the data in a snapshot. Alternatively, you can specify the data of which snaps to forget.

Usage: snap forget [forget-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

get

Print configuration options

The get command prints configuration options for the provided snap.

   $ snap get snap-name username
   frank

If multiple option names are provided, a document is returned:

   $ snap get snap-name username password
   {
       "username": "frank",
       "password": "..."
   }

Nested values may be retrieved via a dotted path:

   $ snap get snap-name author.name
   frank

Usage: snap get [get-OPTIONS]

-t

Strict typing with nulls and quoted strings

-d

Always return document, even with single key

-l

Always return list, even with single key

help

Show help about a command

The help command displays information about snap commands.

Usage: snap help [help-OPTIONS]

--all

Show a short summary of all commands

info

Show detailed information about snaps

The info command shows detailed information about snaps.

The snaps can be specified by name or by path; names are looked for both in the store and in the installed snaps; paths can refer to a .snap file, or to a directory that contains an unpacked snap suitable for 'snap try' (an example of this would be the 'prime' directory snapcraft produces).

Usage: snap info [info-OPTIONS]

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

--verbose

Include more details on the snap (expanded notes, base, etc.)

install

Install snaps on the system

The install command installs the named snaps on the system.

To install multiple instances of the same snap, append an underscore and a unique identifier (for each instance) to a snap's name.

With no further options, the snaps are installed tracking the stable channel, with strict security confinement.

Revision choice via the --revision override requires the the user to have developer access to the snap, either directly or through the store's collaboration feature, and to be logged in (see 'snap help login').

Note a later refresh will typically undo a revision override, taking the snap back to the current revision of the channel it's tracking.

Use --name to set the instance name when installing from snap file.

Usage: snap install [install-OPTIONS]

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

--no-wait

Do not wait for the operation to finish but just print the change id.

--channel

Use this channel instead of stable

--edge

Install from the edge channel

--beta

Install from the beta channel

--candidate

Install from the candidate channel

--stable

Install from the stable channel

--devmode

Put snap in development mode and disable security confinement

--jailmode

Put snap in enforced confinement mode

--classic

Put snap in classic mode and disable security confinement

--revision

Install the given revision of a snap, to which you must have developer access

--dangerous

Install the given snap file even if there are no pre-acknowledged signatures for it, meaning it was not verified and could be dangerous (--devmode implies this)

--unaliased

Install the given snap without enabling its automatic aliases

--name

Install the snap file under the given instance name

--cohort

Install the snap in the given cohort

interface

Show details of snap interfaces

The interface command shows details of snap interfaces.

If no interface name is provided, a list of interface names with at least one connection is shown, or a list of all interfaces if --all is provided.

Usage: snap interface [interface-OPTIONS]

--attrs

Show interface attributes

--all

Include unused interfaces

known

Show known assertions of the provided type

The known command shows known assertions of the provided type. If header=value pairs are provided after the assertion type, the assertions shown must also have the specified headers matching the provided values.

Usage: snap known [known-OPTIONS]

--remote

list

List installed snaps

The list command displays a summary of snaps installed in the current system.

A green check mark (given color and unicode support) after a publisher name indicates that the publisher has been verified.

Usage: snap list [list-OPTIONS]

--all

Show all revisions

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

login

Authenticate to snapd and the store

The login command authenticates the user to snapd and the snap store, and saves credentials into the ~/.snap/auth.json file. Further communication with snapd will then be made using those credentials.

It's not necessary to log in to interact with snapd. Doing so, however, enables purchasing of snaps using 'snap buy', as well as some some developer-oriented features as detailed in the help for the find, install and refresh commands.

An account can be set up at https://login.ubuntu.com

logout

Log out of snapd and the store

The logout command logs the current user out of snapd and the store.

logs

Retrieve logs for services

The logs command fetches logs of the given services and displays them in chronological order.

Usage: snap logs [logs-OPTIONS]

-n <default: "10">

Show only the given number of lines, or 'all'.

-f

Wait for new lines and print them as they come in.

model

Get the active model for this device

The model command returns the active model assertion information for this device.

By default, only the essential model identification information is included in the output, but this can be expanded to include all of an assertion's non-meta headers.

The verbose output is presented in a structured, yaml-like format.

Similarly, the active serial assertion can be used for the output instead of the model assertion.

Usage: snap model [model-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

--serial

Print the serial assertion instead of the model assertion.

--verbose

Print all specific assertion fields.

--assertion

Print the raw assertion.

okay

Acknowledge warnings

The okay command acknowledges the warnings listed with 'snap warnings'.

Once acknowledged a warning won't appear again unless it re-occurrs and sufficient time has passed.

pack

Pack the given directory as a snap

The pack command packs the given snap-dir as a snap and writes the result to target-dir. If target-dir is omitted, the result is written to current directory. If both source-dir and target-dir are omitted, the pack command packs the current directory.

The default file name for a snap can be derived entirely from its snap.yaml, but in some situations it's simpler for a script to feed the filename in. In those cases, --filename can be given to override the default. If this filename is not absolute it will be taken as relative to target-dir.

When used with --check-skeleton, pack only checks whether snap-dir contains valid snap metadata and raises an error otherwise. Application commands listed in snap metadata file, but appearing with incorrect permission bits result in an error. Commands that are missing from snap-dir are listed in diagnostic messages.

Usage: snap pack [pack-OPTIONS]

--check-skeleton

Validate snap-dir metadata only

--filename

Output to this filename

prefer

Enable aliases from a snap, disabling any conflicting aliases

The prefer command enables all aliases of the given snap in preference to conflicting aliases of other snaps whose aliases will be disabled (or removed, for manual ones).

Usage: snap prefer [prefer-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

prepare-image

Prepare a device image

The prepare-image command performs some of the steps necessary for creating device images.

For core images it is not invoked directly but usually via ubuntu-image.

For preparing classic images it supports a --classic mode

Usage: snap prepare-image [prepare-image-OPTIONS]

--classic

Enable classic mode to prepare a classic model image

--arch

Specify an architecture for snaps for --classic when the model does not

--channel <default: "stable">

The channel to use

--snap <snap>[=<channel>]

Include the given snap from the store or a local file and/or specify the channel to track for the given snap

refresh

Refresh snaps in the system

The refresh command updates the specified snaps, or all snaps in the system if none are specified.

With no further options, the snaps are refreshed to the current revision of the channel they're tracking, preserving their confinement options.

Revision choice via the --revision override requires the the user to have developer access to the snap, either directly or through the store's collaboration feature, and to be logged in (see 'snap help login').

Note a later refresh will typically undo a revision override.

Usage: snap refresh [refresh-OPTIONS]

--color <default: "auto">

Use a little bit of color to highlight some things.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

--no-wait

Do not wait for the operation to finish but just print the change id.

--channel

Use this channel instead of stable

--edge

Install from the edge channel

--beta

Install from the beta channel

--candidate

Install from the candidate channel

--stable

Install from the stable channel

--devmode

Put snap in development mode and disable security confinement

--jailmode

Put snap in enforced confinement mode

--classic

Put snap in classic mode and disable security confinement

--amend

Allow refresh attempt on snap unknown to the store

--revision

Refresh to the given revision, to which you must have developer access

--cohort

Refresh the snap into the given cohort

--leave-cohort

Refresh the snap out of its cohort

--list

Show the new versions of snaps that would be updated with the next refresh

--time

Show auto refresh information but do not perform a refresh

--ignore-validation

Ignore validation by other snaps blocking the refresh

remove

Remove snaps from the system

The remove command removes the named snap instance from the system.

By default all the snap revisions are removed, including their data and the common data directory. When a --revision option is passed only the specified revision is removed.

Usage: snap remove [remove-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--revision

Remove only the given revision

--purge

Remove the snap without saving a snapshot of its data

restart

Restart services

The restart command restarts the given services.

If the --reload option is given, for each service whose app has a reload command, a reload is performed instead of a restart.

Usage: snap restart [restart-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--reload

If the service has a reload command, use it instead of restarting.

restore

Restore a snapshot

The restore command replaces the current user, system and configuration data of included snaps, with the corresponding data from the specified snapshot.

By default, this command restores all the data in a snapshot. Alternatively, you can specify the data of which snaps to restore, or for which users, or a combination of these.

If a snap is included in a restore operation, excluding its system and configuration data from the restore is not currently possible. This restriction may be lifted in the future.

Usage: snap restore [restore-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--users

Restore data of only specific users (comma-separated) (default: all users)

revert

Reverts the given snap to the previous state

The revert command reverts the given snap to its state before the latest refresh. This will reactivate the previous snap revision, and will use the original data that was associated with that revision, discarding any data changes that were done by the latest revision. As an exception, data which the snap explicitly chooses to share across revisions is not touched by the revert process.

Usage: snap revert [revert-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--devmode

Put snap in development mode and disable security confinement

--jailmode

Put snap in enforced confinement mode

--classic

Put snap in classic mode and disable security confinement

--revision

Revert to the given revision

run

Run the given snap command

The run command executes the given snap command with the right confinement and environment.

Usage: snap run [run-OPTIONS]

--shell

Run a shell instead of the command (useful for debugging)

--strace [="with-strace"] <default: "no-strace">

Run the command under strace (useful for debugging). Extra strace options can be specified as well here. Pass --raw to strace early snap helpers.

--gdb

Run the command with gdb

--trace-exec

Display exec calls timing data

save

Save a snapshot of the current data

The save command creates a snapshot of the current user, system and configuration data for the given snaps.

By default, this command saves the data of all snaps for all users. Alternatively, you can specify the data of which snaps to save, or for which users, or a combination of these.

If a snap is included in a save operation, excluding its system and configuration data from the snapshot is not currently possible. This restriction may be lifted in the future.

Usage: snap save [save-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display short relative times.

--users

Snapshot data of only specific users (comma-separated) (default: all users)

saved

List currently stored snapshots

The saved command displays a list of snapshots that have been created previously with the 'save' command.

Usage: snap saved [saved-OPTIONS]

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display short relative times.

--id

Show only a specific snapshot.

services

Query the status of services

The services command lists information about the services specified, or about the services in all currently installed snaps.

set

Change configuration options

The set command changes the provided configuration options as requested.

   $ snap set snap-name username=frank password=$PASSWORD

All configuration changes are persisted at once, and only after the snap's configuration hook returns successfully.

Nested values may be modified via a dotted path:

   $ snap set snap-name author.name=frank

Configuration option may be unset with exclamation mark:
   $ snap set snap-name author!

Usage: snap set [set-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

start

Start services

The start command starts, and optionally enables, the given services.

Usage: snap start [start-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--enable

As well as starting the service now, arrange for it to be started on boot.

stop

Stop services

The stop command stops, and optionally disables, the given services.

Usage: snap stop [stop-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--disable

As well as stopping the service now, arrange for it to no longer be started on boot.

switch

Switches snap to a different channel

The switch command switches the given snap to a different channel without doing a refresh.

Usage: snap switch [switch-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--channel

Use this channel instead of stable

--edge

Install from the edge channel

--beta

Install from the beta channel

--candidate

Install from the candidate channel

--stable

Install from the stable channel

--cohort

Switch the snap into the given cohort

--leave-cohort

Switch the snap out of its cohort

tasks

List a change's tasks

The tasks command displays a summary of tasks associated with an individual change.

Usage: snap tasks [tasks-OPTIONS]

Aliases: change
--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

--last

Select last change of given type (install, refresh, remove, try, auto-refresh, etc.). A question mark at the end of the type means to do nothing (instead of returning an error) if no change of the given type is found. Note the question mark could need protecting from the shell.

try

Test an unpacked snap in the system

The try command installs an unpacked snap into the system for testing purposes. The unpacked snap content continues to be used even after installation, so non-metadata changes there go live instantly. Metadata changes such as those performed in snap.yaml will require reinstallation to go live.

If snap-dir argument is omitted, the try command will attempt to infer it if either snapcraft.yaml file and prime directory or meta/snap.yaml file can be found relative to current working directory.

Usage: snap try [try-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

--devmode

Put snap in development mode and disable security confinement

--jailmode

Put snap in enforced confinement mode

--classic

Put snap in classic mode and disable security confinement

unalias

Remove a manual alias, or the aliases for an entire snap

The unalias command removes a single alias if the provided argument is a manual alias, or disables all aliases of a snap, including manual ones, if the argument is a snap name.

Usage: snap unalias [unalias-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

unset

Remove configuration options

The unset command removes the provided configuration options as requested.

$ snap unset snap-name name address

All configuration changes are persisted at once, and only after the snap's configuration hook returns successfully.

Nested values may be removed via a dotted path:

$ snap unset snap-name user.name

Usage: snap unset [unset-OPTIONS]

--no-wait

Do not wait for the operation to finish but just print the change id.

version

Show version details

The version command displays the versions of the running client, server, and operating system.

wait

Wait for configuration

The wait command waits until a configuration becomes true.

warnings

List warnings

The warnings command lists the warnings that have been reported to the system.

Once warnings have been listed with 'snap warnings', 'snap okay' may be used to silence them. A warning that's been silenced in this way will not be listed again unless it happens again, _and_ a cooldown time has passed.

Warnings expire automatically, and once expired they are forgotten.

Usage: snap warnings [warnings-OPTIONS]

--abs-time

Display absolute times (in RFC 3339 format). Otherwise, display relative times up to 60 days, then YYYY-MM-DD.

--unicode <default: "auto">

Use a little bit of Unicode to improve legibility.

--all

Show all warnings

--verbose

Show more information

watch

Watch a change in progress

The watch command waits for the given change-id to finish and shows progress (if available).

Usage: snap watch [watch-OPTIONS]

--last

Select last change of given type (install, refresh, remove, try, auto-refresh, etc.). A question mark at the end of the type means to do nothing (instead of returning an error) if no change of the given type is found. Note the question mark could need protecting from the shell.

whoami

Show the email the user is logged in with

The whoami command shows the email the user is logged in with.

Info

25 November 2019