---
name: "snapper"
section: "8"
platform: "linux"
package: "snapper"
version: "0.13.2-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/snapper"
---

# snapper(8)

Command-line program for filesystem snapshot management

## NAME

snapper - Command-line program for filesystem snapshot management

## SYNOPSIS

**snapper** \[*--global-opts*\] *command* \[*--command-opts*\] \[*command-arguments*\]

**snapper** {--help}

## DESCRIPTION

Snapper is a command-line program for filesystem snapshot management. It can create, delete and compare snapshots and undo changes done between snapshots.

Snapper never modifies the content of snapshots. Thus snapper creates read-only snapshots if supported by the kernel. Supported filesystems are btrfs and ext4 (discontinued) as well as snapshots of LVM logical volumes with thin-provisioning. Some filesystems might not be supported depending on your installation.

## CONCEPTS

### Configurations

For each filesystem or subvolume that should be snapshotted by snapper, a configuration file is required, see [**snapper-configs**(5)](/snapper-configs/5.md). The setup can be done with the create-config command.

### Snapshots

Snapper distinguishes three types of snapshots.

pre

Pre snapshots should always have a corresponding post snapshot. The intention of pre/post snapshot pairs is to snapshot the filesystem before and after a modification.

post

See pre type.

single

These snapshots have no special relationship to other snapshots.

Note that filesystem-wise all three types are the same.

### Snapshot Description and Userdata

With each snapshot a description and some userdata can be associated. The description is a string. The userdata is a list of key-value pairs where the keys and values are strings.

Do not use non-ASCII characters for the snapshot description, userdata or any other strings, unless you always use the UTF-8 character encoding.

### Automatic Snapshot Creation

Next to manual snapshot creation, snapshots are also created automatically.

• A cronjob or systemd timer creates hourly snapshots, if TIMELINE\_CREATE is enabled for a config.

• Certain programs like YaST and zypper create pre/post snapshot pairs when modifying the system.

### Cleanup Algorithms

Snapper provides several algorithms to clean up old snapshots. The algorithms are executed in an hourly cronjob or systemd timer. This can be configured in the corresponding configurations files along with parameters for every algorithm.

number

Deletes old snapshots when a certain number of snapshots is reached.

timeline

Deletes old snapshots but keeps a number of hourly, daily, weekly, monthly, quarterly and yearly snapshots.

empty-pre-post

Deletes pre/post snapshot pairs with empty diffs.

The number and timeline cleanup algorithms can also try to keep the space used by snapshots below a limit and the free space of the filesystem above a limit. For the first condition quota must be setup, see command setup-quota. Additionally the NUMBER\_LIMIT and TIMELINE\_LIMIT variables in the config file must have ranges (min- and max-value). The algorithms will then make two passes:

 1\. Delete snapshots above the max-value independent of the snapshot and filesystem space.

 2\. Delete snapshots above the min-value until the limits for the snapshot and filesystem are reached.

The limit for the used space can be configured via the SPACE\_LIMIT variable. Note: Only snapshots that have a cleanup algorithm set are taken into account when calculating the space used by snapshots.

The limit for the free space can be configured via the FREE\_LIMIT variable.

Note: Since the cleanup is performed asynchronously from creating snapshots the observed snapshots can differ from the expected snapshots according to the limits. Also btrfs stale qgroups can exist temporarily.

### Filters

Some files keep state information of the system, e.g. /etc/mtab. Such files should never be reverted. To help users, snapper allows one to ignore these files.

Filters are read from the files /etc/snapper/filters/\*.txt and /usr/share/snapper/filters/\*.txt, where for files with the same name the former location has precedence. Each line in those files specifies a pattern. When snapper computes the difference between two snapshots it ignores all files and directories matching any of those patterns by using [**fnmatch**(3)](/fnmatch/3.md) with the flag FNM\_LEADING\_DIR.

Note that filters do not exclude files or directories from being snapshotted. For that, use subvolumes or mount points.

## GLOBAL OPTIONS

- **-q, --quiet**

  Suppress normal output. Error messages will still be printed, though.

- **-v, --verbose**

  Increase verbosity.

- **--logger-type** *type*

  Set the logger type. Possible values are none, stdout, logfile and syslog.

- **--debug**

  Turn on debugging.

- **--utc**

  Display dates and times in UTC. By default, local time is used.

- **--iso**

  Display dates and times in ISO format. ISO format is always used for machine-readable outputs.

- **-t, --table-style** *style*

  Specifies table style. Table style is identified by an integer number.

- **--abbreviate**

  Try to abbreviate texts in some columns so that tables fit the width of the screen.

- **--machine-readable** *format*

  Specifies a machine-readable output format. Possible options are csv and json.

- **--csvout**

  Sets CSV output format. See **RFC 4180**\[1\] for the details, except lines end with a LF, not CR+LF.

- **--jsonout**

  Sets JSON output format.

- **--separator** *character*

  Specifies the character separator for CSV output format.

- **--no-headers**

  Suppress headers for CSV output format.

- **-c, --config** *name*

  Use specified configuration instead of the default configuration. The default configuration is named "root".

- **--no-dbus**

  Operate without a DBus connection.

  Use with caution since a running snapperd will not know about modifications made to the system.

- **-r, --root** *path*

  Operate on target root. Only works together with no-dbus and only for some commands.

- **-a, --ambit** *ambit*

  Operate in the specified ambit. Can be used to override the ambit detection. Allowed ambits are auto, classic and transactional.

- **--version**

  Print version and exit.

## COMMANDS

Snapper provides a number of *commands*. Each command accepts the options listed in the GLOBAL OPTIONS section. These options must be specified *before* the command name. In addition, many commands have specific options, which are listed in this section. These command-specific options must be specified *after* the name of the command and *before* any of the command arguments.

**help**

Show short help text.

**list-configs \[options\]**

List available configurations.

- **--columns** *columns*

  Select columns to show separated by comma.

  Possible columns are: config, subvolume.

**create-config \[options\]** *subvolume*

Create a new configuration for a filesystem or subvolume. For this command you will likely need the global option **--config**, see GLOBAL OPTIONS and CONCEPTS.

- **-f, --fstype** *fstype*

  Manually set filesystem type. Supported values are btrfs, ext4 (discontinued) and lvm. For lvm, snapper uses LVM thin-provisioned snapshots. The filesystem type on top of LVM must be provided in parentheses, e.g. lvm(xfs).

  Without this option snapper tries to detect the filesystem.

- **-t, --template** *name*

  Name of template for the new configuration file.

**delete-config**

Delete a configuration for a filesystem or subvolume including all snapshots. For this command you will likely need to global option **--config**, see GLOBAL OPTIONS and CONCEPTS.

**get-config \[options\]**

Displays the settings of the configuration.

- **--columns** *columns*

  Select columns to show separated by comma.

  Possible columns are: key, value.

  Columns are not selected when JSON format is used.

**set-config** *configdata*

Changes the settings of the configuration. The settings *configdata* are a list of key-value-pairs separated by spaces and the key and value must be separated by an equal sign, e.g. "NUMBER\_CLEANUP=yes NUMBER\_LIMIT=10". The value of SUBVOLUME and FSTYPE cannot be changed.

**list (ls) \[options\]**

List snapshots.

- **-t, --type** *type*

  Selects type of snapshots to list. Possible values are all, single and pre-post.

- **--disable-used-space**

  Disable display of used space.

  Calculating the used space needs some time. Thus this option can speed up the listing.

- **-a, --all-configs**

  List snapshots from all configs accessible by the user.

- **--columns** *columns*

  Select columns to show separated by comma.

  Possible columns are: config, subvolume, number, default, active, date, user, used-space, cleanup, description, userdata, pre-number, post-number, post-date, read-only.

For each snapshot the output consists of several columns. Some need explanation:

\#, Pre # and Post #

The number of the snapshot.

For btrfs the number can be followed by a sign. A "-" indicates that the snapshot is the currently mounted snapshot and a "+" indicates that the snapshot will be mounted next time (It is the btrfs default subvolume). If both conditions apply a "\*" is displayed.

Used Space

For btrfs the exclusive space of the btrfs quota group corresponding to the snapshot.

Display of used space is automatically disabled if not available, e.g. quota not enabled on btrfs.

**create \[options\]**

Create a new snapshot.

- **-t, --type** *type*

  Specifies the type of the new snapshot. Possible values are single, pre and post.

- **--pre-number** *number*

  For post snapshots the number of the pre snapshot must be provided.

- **-p, --print-number**

  Print number of the created snapshot.

- **-d, --description** *description*

  Description for the snapshot.

- **-c, --cleanup-algorithm** *cleanup-algorithm*

  Set the cleanup algorithm for the snapshot.

- **-u, --userdata** *userdata*

  Set userdata for the snapshot. The key-value pairs must be separated by comma and the key and value must be separated by an equal sign, e.g. requestid=42,user=arthur.

- **--command** *command*

  Create a pre and post snapshot and run command in between. If snapper is unable to execute the command at all, it does not take the post snapshot. If the command exits with a non-zero exit code, snapper takes the post snapshot and exits with that same exit code.

- **--read-only**

  Create a read-only snapshot. This is the default.

- **--read-write**

  Create a read-write snapshot.

- **--from** *number*

  Create a snapshot from the snapshot with the provided number instead of snapshot 0.

- **--empty**

  Create an empty snapshot. Only supported on btrfs and with --no-dbus.

**modify \[options\]** *number*

Modify a snapshot.

- **-d, --description** *description*

  New description for snapshot.

- **-c, --cleanup-algorithm** *cleanup-algorithm*

  Set the cleanup algorithm for the snapshot.

- **-u, --userdata** *userdata*

  Set userdata for the snapshot. The key-value pairs must be separated by comma and the key and value must be separated by an equal sign, e.g. requestid=42,user=arthur.

- **--read-only**

  Set the snapshot read-only.

- **--read-write**

  Set the snapshot read-write.

- **--default**

  Set the snapshot as default snapshot. Only for btrfs.

**delete (remove\|rm)** *number* **\|** *number1-number2*

Delete a snapshot or a range of snapshots.

- **-s, --sync**

  Sync the filesystem after deleting the snapshots. The details depend on the filesystem type.

  Btrfs normally asynchronously frees space after deleting snapshots. With this option snapper will wait until the space once used by the deleted snapshots is actually available again.

Snapshot 0 cannot be deleted. For btrfs the currently mounted snapshot and the snapshot that will be mounted next time (the btrfs default subvolume) can also not be deleted.

**mount** *number*

Mount a snapshot. Not required for all filesystem types.

**umount** *number*

Unmount a snapshot. Not required for all filesystem types.

**status \[options\]** *number1***..***number2*

Compare the snapshots *number1* and *number2*. This will show a list of files and directories that have been created, modified or deleted in the time between the two snapshots have been made.

- **-o, --output** *file*

  Write output to file *file*.

The output consists of a string encoding the status followed by the filename. The characters of the status string are:

 1\. A "+" means the file was created, a "-" means the file was deleted. A "c" means the content of the file has changed and a "t" means the type of the file has changed (e.g. from regular file to directory).

 2\. A "p" means the permissions have changed.

 3\. An "u" means the user ownership has changed.

 4\. A "g" means the group ownership has changed.

 5\. A "x" means the extended attribute information has changed.

 6\. An "a" means the ACL information has changed.

If there is no change a "." is outputted.

**diff \[options\]** *number1***..***number2* **\[files\]**

Compare the snapshots *number1* and *number2*. This will show a diff of the content of files and directories that have been created, modified or deleted in the time between the two snapshots have been made.

- **-i, --input** *file*

  Read files to diff from file *file*.

- **--diff-cmd** *command*

  Command used for comparing files. The default is /usr/bin/diff --new-file --unified. The two files to compare are passed as parameters to the command.

- **-x, --extensions** *options*

  Extra options passed to the diff command.

**undochange \[options\]** *number1***..***number2* **\[files\]**

Undo changes done between snapshot *number1* and *number2*.

- **-i, --input** *file*

  Read files for which to undo changes from file *file*.

**rollback \[options\] \[***number***\]**

Creates two new snapshots and sets the default subvolume. Per default the system boots from the default subvolume of the root filesystem. The exact actions depend on whether a number is provided or not:

• Without a number, a first read-only snapshot of the default subvolume is created. A second read-write snapshot of the current system is created. The system is set to boot from the second snapshot.

• With a number, a first read-only snapshot of the current system is created. A second read-write snapshot is created of *number*. The system is set to boot from the second snapshot.

Rollback is only supported with btrfs and requires a properly configured system.

- **-p, --print-number**

  Print number of the second created snapshot.

- **-d, --description** *description*

  Description for the snapshot.

- **-c, --cleanup-algorithm** *cleanup-algorithm*

  Set the cleanup algorithm for the snapshot.

- **-u, --userdata** *userdata*

  Set userdata for the snapshot. The key-value pairs must be separated by comma and the key and value must be separated by an equal sign, e.g. requestid=42,user=arthur.

The rollback command also sets the description, the cleanup algorithm and some userdata unless the values are specified on the command line. This will automate cleanup of snapshots created by rollbacks.

In other ambits than classic the rollback command does what is required to do a rollback. Anyway it is recommended to use specific programs in that case.

**setup-quota**

Sets up quota. Currently only supported with btrfs.

**cleanup \[options\]** *cleanup-algorithm*

Run the cleanup algorithm *cleanup-algorithm*. Currently implemented cleanup algorithms are number, timeline and empty-pre-post. To run all cleanup algorithms, all can be provided as cleanup-algorithm.

- **--path** *path*

  Cleanup all configs affecting path. Only useful for btrfs.

- **--free-space** *free-space*

  Try to make free-space available. Only useful for btrfs.

**xadiff** *number1***..***number2* **\[files\]**

Compare the extended attributes between snapshot *number1* and *number2*. See examples below:

• +:user.foo for created attributes

• -:user.bar for removed attributes

• -+:security.selinux for modified attributes

## PERMISSIONS

Non-root users can be allowed to use a configuration by setting ALLOW\_USERS or ALLOW\_GROUPS in the config file. For all operations to work, the user must also be able to read and access the .snapshots directory inside the subvolume. The .snapshots directory must be owned by root and must not be writable by anybody else.

Here are some methods how to achieve that:

• Make the directory accessible for everyone:

**chmod a+rx .snapshots**

• Make the directory accessible for a group the user belongs to, e.g.:

**chown :users .snapshots**

• Make the directory accessible for the user using ACLs, e.g.:

**setfacl -m u:tux:rx .snapshots**

The last method can be performed by snapper, see the SYNC\_ACL setting in [**snapper-configs**(5)](/snapper-configs/5.md).

## PLUGINS

snapper can execute external scripts after certain actions. Scripts have to be placed in /usr/lib/snapper/plugins. The name has to start with a digit, execution order is alphabetical.

The first argument of a script is the action snapper executed. The following actions are defined:

**create-config-pre** *subvolume* *fstype*

Executed before a new config is created

**create-config-post** *subvolume* *fstype*

Executed after a new config was created

**delete-config-pre** *subvolume* *fstype*

Executed before a config is deleted

**delete-config-post** *subvolume* *fstype*

Executed after a config was deleted

**create-snapshot-pre** *subvolume* *fstype* *snapshot-number*

Executed before a new snapshot is created

**create-snapshot-post** *subvolume* *fstype* *snapshot-number*

Executed after a new snapshot was created

**modify-snapshot-pre** *subvolume* *fstype* *snapshot-number*

Executed before a snapshot is modified

**modify-snapshot-post** *subvolume* *fstype* *snapshot-number*

Executed after a snapshot was modified

**delete-snapshot-pre** *subvolume* *fstype* *snapshot-number*

Executed before a snapshot is removed

**delete-snapshot-post** *subvolume* *fstype* *snapshot-number*

Executed after a snapshot was removed

**set-read-only-pre** *subvolume* *fstype* *snapshot-number*

Executed before a snapshot is set read-only or read-write

**set-read-only-post** *subvolume* *fstype* *snapshot-number*

Executed after a snapshot is set read-only or read-write

**set-default-snapshot-pre** *subvolume* *fstype* *snapshot-number*

Executed before the default snapshot is changed

**set-default-snapshot-post** *subvolume* *fstype* *snapshot-number*

Executed after the default snapshot was changed

**rollback-post** *subvolume* *fstype* *old-snapshot-number* *new-snapshot-number*

Executed after a rollback was done

More actions and arguments can be added any time. Using snapper in the plugins is not allowed.

Ensure plugins execute within a few seconds. Slow-running plugins block the primary interface and degrade user experience and can even cause timeouts (e.g. causing zypper to kill the snapper plugin).

It is undefined whether the plugins are called from the client (snapper) or server (snapperd).

## FILES

/etc/conf.d/snapper

Global configuration file.

/etc/snapper/configs

Directory containing configuration files.

/etc/snapper/config-templates

Directory containing configuration templates.

/usr/share/snapper/config-templates

Fallback directory containing configuration templates.

/etc/snapper/filters/\*.txt

Filter files.

/usr/share/snapper/filters/\*.txt

Fallback filter files.

/var/log/snapper.log

Logfile. Please include this file in bug reports.

## EXIT STATUS

Normally the exit status is 0. If an error occurred the exit status is 1. It is also an error if the exit status of a plugin is not 0.

## NOTES

There is no mechanism to ensure consistency of the files while a snapshot is made. E.g. the files of a database can be inconsistent while the database is running.

Consistency after undochange is not guaranteed. E.g. when the creation of a user is undone, there might still exist files from that user.

Support for individual filesystems, rollback and extended attributes are compile-time options and may not be available.

## HOMEPAGE

**http://snapper.io/**

## AUTHORS

Arvin Schnell \<aschnell@suse.com\>

## SEE ALSO

[**snapper-configs**(5)](/snapper-configs/5.md), **snapper-zypp-plugin**(8), [**snbk**(8)](/snbk/8.md), [**pam\_snapper**(8)](/pam_snapper/8.md), [**btrfs**(8)](/btrfs/8.md), [**lvm**(8)](/lvm/8.md), [**attr**(5)](/attr/5.md), [**acl**(5)](/acl/5.md)

## NOTES

- 1\.

  RFC 4180

  https://tools.ietf.org/html/rfc4180