diff --git a/DC-snapper-undo-changes b/DC-snapper-undo-changes
new file mode 100644
index 000000000..e0c351df5
--- /dev/null
+++ b/DC-snapper-undo-changes
@@ -0,0 +1,17 @@
+# This file originates from the project https://github.com/openSUSE/doc-kit
+# This file can be edited downstream.
+
+MAIN="snapper-undo-changes.asm.xml"
+ROOTID="snapper-undo-changes"
+SRC_DIR="articles"
+IMG_SRC_DIR="images"
+
+PROFOS="generic"
+#PROFCONDITION="suse-product"
+#PROFCONDITION="suse-product;beta"
+#PROFCONDITION="community-project"
+
+STYLEROOT="/usr/share/xml/docbook/stylesheet/suse2022-ns"
+FALLBACK_STYLEROOT="/usr/share/xml/docbook/stylesheet/suse2022-ns"
+DOCBOOK5_RNG_URI="urn:x-suse:rng:v2:geekodoc-flat"
+XSLTPARAM="--param generate.json-ld=1 "
diff --git a/articles/snapper-undo-changes.asm.xml b/articles/snapper-undo-changes.asm.xml
new file mode 100644
index 000000000..308a7b253
--- /dev/null
+++ b/articles/snapper-undo-changes.asm.xml
@@ -0,0 +1,169 @@
+
+
+
+
+ %entities;
+]>
+
+
+
+
+
+
+
+
+
+ For more information
+
+
+ Comparing rollback and undoing changes
+
+
+
+
+
+ Introduction
+
+
+ Undoing &yast; and &zypper; changes
+
+
+ Restoring files with &snapper;
+
+
+
+
+
+ Legal Notice
+
+
+ GNU Free Documentation License
+
+
+
+
+
+ Using &snapper; to undo changes
+
+ 2024-01-04
+
+
+ This topic merges and updates the content about using Snapper to
+ undo changes and restore files from the Snapper chapter 10.2 in
+ the &productname; Admin Guide.
+
+
+
+
+
+
+
+ &x86-64;
+ &power;
+ &zseries;
+ &aarch64;
+
+
+ &alp;
+
+ Using &snapper; to undo changes
+ How to use &snapper; to undo &yast; and &zypper; changes
+ and restore files; comparison between undoing changes and rollback
+ Undo &yast; and &zypper; changes with &snapper;
+
+ Backup & Recovery
+ Administration
+
+ Products & Solutions
+
+
+ https://bugzilla.suse.com/enter_bug.cgi
+ Smart Docs
+ Documentation
+ daria.vladykina@suse.com
+
+ yes
+
+
+
+
+ WHAT?
+
+
+ This article describes how to use &snapper; in its default configuration
+ to undo changes performed with &yast; and &zypper; and to restore files.
+
+
+
+
+ WHY?
+
+
+ You aim to learn about &snapper;'s most commonly used functionality: undoing changes.
+
+
+
+
+ EFFORT
+
+
+ It takes up to 15 minutes to read about reverting changes and restoring files
+ with &snapper;.
+
+
+
+
+ REQUIREMENTS
+
+
+
+
+ &rootuser; or &sudo; privileges
+
+
+
+
+ Snapper needs to be installed. It is available on &productname; by default.
+
+
+
+
+ The root partition (/) size of at least 16 GB.
+
+
+
+
+
+
+
+ This article is the second installment of the series of articles
+ about &snapper;. In the first article, we covered the core principles
+ of &snapper;—see
+ The Basic Concepts of Snapper.
+ Subsequent articles will cover &snapper;'s other use cases such as rolling
+ back the system, manually creating and managing snapshots, and automatic
+ snapshot cleanup.
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/concepts/snapper-undo-changes-intro.xml b/concepts/snapper-undo-changes-intro.xml
new file mode 100644
index 000000000..4d5f2af35
--- /dev/null
+++ b/concepts/snapper-undo-changes-intro.xml
@@ -0,0 +1,96 @@
+
+
+ %entities;
+
+
+
+
+]>
+
+
+
+
+
+
+ Default configuration
+
+
+
+ &snapper; on &productname; is preconfigured to serve as a tool that lets you
+ undo changes made by zypper and &yast;. It does this
+ by creating a pair of snapshots before and after each run of zypper
+ and &yast;.
+
+
+
+ Taking snapshot pairs upon installing packages with &yast; or &zypper; is
+ handled by snapper-zypp-plugin. An XML
+ configuration file, /etc/snapper/zypp-plugin.conf, defines
+ when to make snapshots. By default, the file looks like the following:
+
+
+<?xml version="1.0" encoding="utf-8"?>
+<snapper-zypp-plugin-conf>
+<solvables>
+<solvable match="w" important="true">kernel-*</solvable>
+<solvable match="w" important="true">dracut</solvable>
+<solvable match="w" important="true">glibc</solvable>
+<solvable match="w" important="true">systemd*</solvable>
+<solvable match="w" important="true">udev</solvable>
+<solvable match="w">*</solvable>
+</solvables>
+</snapper-zypp-plugin-conf>
+
+
+
+ The match attribute defines whether the pattern is a Unix shell-style
+ wild card (w) or a Python regular expression
+ (re). For more information about regular expressions in Python,
+ refer to Regular expression operations.
+
+
+
+
+ If the pattern matches and the corresponding package is marked as
+ important (for example, kernel packages), the snapshot will also be
+ marked as important.
+
+
+
+
+ Pattern to match a package name. Based on the setting of the
+ match attribute, special characters are
+ interpreted as shell wild cards or regular expressions. This pattern
+ matches all package names, starting with kernel-.
+
+
+
+
+ This line unconditionally matches all packages.
+
+
+
+
+ With this configuration snapshot, pairs are made whenever a package is
+ installed (see ). When the kernel, dracut, glibc, systemd, or udev packages
+ marked as important are installed, the snapshot pair will also be marked
+ as important. All rules are evaluated.
+
+ By default, automatic snapshots as described above are configured for the
+ root partition and its subvolumes. To make snapshots available for other
+ partitions such as /home, for example, you can create
+ custom configurations.
+
+ &snapper; also lets you restore system files that have been accidentally
+ deleted or modified. Timeline snapshots for the root partition need to be
+ enabled for this purpose.
+
+
diff --git a/glues/snapper-undo-changes-compare-undo-and-rollback.xml b/glues/snapper-undo-changes-compare-undo-and-rollback.xml
new file mode 100644
index 000000000..754584c75
--- /dev/null
+++ b/glues/snapper-undo-changes-compare-undo-and-rollback.xml
@@ -0,0 +1,63 @@
+
+
+ %entities;
+
+]>
+
+
+ Undoing changes compared to rollback with &snapper;
+
+
+ When working with snapshots to restore data, it is important to know that
+ there are two fundamentally different scenarios &snapper; can handle:
+ undoing changes and rollback. The key difference between them is the level
+ of granularity and the scope of the operation.
+
+
+
+
+
+ Undoing changes with &snapper;
+ To undo changes made between two snapshots, the undochange
+ command is used. This command allows you to reverse the effects of a specific
+ action within a transaction without impacting subsequent changes. For example,
+ if you have a configuration file that was modified in a certain snapshot and
+ you want to revert that change, use the undochange
+ command to do so.
+
+ When undoing changes, two snapshots are
+ being compared and the changes between these two snapshots are made
+ undone. Using this method, you can explicitly select the files
+ that need to be restored.
+
+
+
+
+ Rollback with &snapper;
+ In comparison with undoing changes, a rollback is a more comprehensive
+ operation that reverts the entire file system to a previous snapshot, including
+ configurations and system files. This is useful when you want to revert
+ multiple transactions and return the system to a previous state, erasing
+ all changes made after a specific transaction.
+
+ When doing rollbacks,
+ the system is reset to the state at which the snapshot was taken.
+
+
+ When undoing changes, it is also possible to compare a snapshot against the
+ current system. When restoring all files from such a
+ comparison, this will have the same result as doing a rollback.
+
+
+
diff --git a/glues/snapper-undo-changes-more-info.xml b/glues/snapper-undo-changes-more-info.xml
new file mode 100644
index 000000000..04ab983df
--- /dev/null
+++ b/glues/snapper-undo-changes-more-info.xml
@@ -0,0 +1,50 @@
+
+
+ %entities;
+
+]>
+
+
+ For more information
+
+
+
+
+
+
+
+
+ For more detailed information on how to do system rollback by
+ booting from snapshots, see
+
+
+
+
+
+ For more information on creating additional &snapper; configurations, see
+
+
+
+
+
+ For more information about backup snapshots, see
+
+
+
+
+
+ For more information about creating custom configurations, see
+
+
+
+
+
diff --git a/images/snapper-yast-changes.png b/images/snapper-yast-changes.png
new file mode 100644
index 000000000..879c90573
Binary files /dev/null and b/images/snapper-yast-changes.png differ
diff --git a/images/snapper-yast-diff.png b/images/snapper-yast-diff.png
new file mode 100644
index 000000000..b8b156f9d
Binary files /dev/null and b/images/snapper-yast-diff.png differ
diff --git a/images/snapper-yast-list.png b/images/snapper-yast-list.png
new file mode 100644
index 000000000..cfa4cb7e7
Binary files /dev/null and b/images/snapper-yast-list.png differ
diff --git a/images/snapper-yast-restore.png b/images/snapper-yast-restore.png
new file mode 100644
index 000000000..087a04e17
Binary files /dev/null and b/images/snapper-yast-restore.png differ
diff --git a/tasks/snapper-undo-changes-restore-files.xml b/tasks/snapper-undo-changes-restore-files.xml
new file mode 100644
index 000000000..b99a7a2f2
--- /dev/null
+++ b/tasks/snapper-undo-changes-restore-files.xml
@@ -0,0 +1,165 @@
+
+
+ %entities;
+
+
+
+]>
+
+
+
+
+
+
+ Using &snapper; to restore files
+
+
+
+ &snapper; provides the functionality to restore system files that may
+ have been accidentally deleted or modified, or to restore previous versions
+ of files.
+
+
+ To use the restore feature, timeline snapshots for the root partition
+ must be activated. They provide a historical record of the state of the file
+ system over time. This allows you to select a specific snapshot to restore
+ from, rather than having to restore the entire file system.
+ You can also find out which modifications were made at a certain point
+ in time. To do so, use &snapper;'s diff feature.
+
+ Being able to restore files is especially interesting for data that may
+ reside on subvolumes or partitions for which snapshots are not taken by
+ default. For example, to restore files from home directories, you need to
+ create a separate &snapper; configuration for /home
+ doing automatic timeline snapshots.
+
+
+ Restoring files compared to rollback
+
+ Snapshots taken from the root file system (defined by &snapper;'s root
+ configuration) can be used to do a system rollback. The recommended way
+ to do such a rollback is to boot from the snapshot and then perform the
+ rollback.
+
+
+ Performing a rollback would also be possible by restoring all files from a
+ root file system snapshot as described below. However, this is not
+ recommended. You may restore single files, for example, a configuration
+ file from the /etc directory, but not the
+ complete list of files from the snapshot.
+
+
+ This restriction only affects snapshots taken from the root file system.
+
+
+
+ Restoring files using the &yast; <guimenu>Snapper</guimenu> module
+ To restore files with the &snapper; module in &yast;, follow these steps:
+
+
+ Open the Miscellaneous section in &yast; or enter the command
+ yast2 snapper to open it, and start the Filesystem
+ Snapshots module.
+
+
+
+
+ Select the Current Configuration from which to choose
+ a snapshot.
+
+
+
+
+ Select a timeline snapshot from which to restore a file and click
+ Show Changes. Timeline snapshots are of the type
+ Single with a description value of
+ timeline.
+
+
+
+
+ Select a file from the text box by clicking the file name. The difference
+ between the snapshot version and the current system is shown. Activate
+ the check box to select the file for restore. Do so for all files you
+ want to restore.
+
+
+
+
+ Click Restore Selected and confirm the action by
+ clicking Yes.
+
+
+
+
+ Restoring files using the <command>snapper</command> command
+ To restore files with the snapper command, perform
+ the following steps:
+
+
+ Get a list of timeline snapshots for a specific configuration by running
+ the following command:
+
+ &prompt.sudo;snapper -c CONFIG list -t single | grep timeline
+
+ CONFIG needs to be replaced by an existing
+ &snapper; configuration. Use snapper list-configs to
+ display a list.
+
+
+
+
+ Get a list of changed files for a given snapshot by running the following
+ command:
+
+ &prompt.sudo;snapper -c CONFIG status SNAPSHOT_ID..0
+
+ Replace SNAPSHOT_ID with the ID for the snapshot
+ from which you want to restore the files.
+
+
+
+
+ Optionally list the differences between the current file version and the
+ one from the snapshot by running
+
+ &prompt.sudo;snapper -c CONFIG diff SNAPSHOT_ID..0 FILE NAME
+
+ If you do not specify <FILE NAME>, the
+ difference for all files is shown.
+
+
+
+
+ To restore one or more files, run
+
+ &prompt.sudo;snapper -c CONFIG -v undochange SNAPSHOT_ID..0 FILENAME1FILENAME2
+
+ If you do not specify file names, all changed files will be restored.
+
+
+
+
+
+ Data consistency
+
+ There is no mechanism to ensure data consistency when creating a snapshot.
+ Whenever a file (for example, a database) is written at the same time as the
+ snapshot is being created, it will result in a corrupted or partly written
+ file. Restoring such a file will cause problems. Furthermore, certain system
+ files, such as /etc/mtab, must never be restored.
+ Therefore, we strongly recommend to always closely
+ review the list of changed files and their diffs. Only restore files that
+ really belong to the action you want to revert.
+
+
+
+
diff --git a/tasks/snapper-undo-changes-yast-zypper.xml b/tasks/snapper-undo-changes-yast-zypper.xml
new file mode 100644
index 000000000..6e94fe62c
--- /dev/null
+++ b/tasks/snapper-undo-changes-yast-zypper.xml
@@ -0,0 +1,274 @@
+
+
+ %entities;
+
+
+
+
+]>
+
+
+
+
+
+
+ Undoing &yast; and &zypper; changes
+
+
+
+ When the root partition is set up with Btrfs during the
+ installation, &snapper; is installed automatically and is preconfigured for
+ doing rollbacks of &yast; and &zypper; changes. Every time you start
+ a &yast; module or a &zypper; transaction, two snapshots are created: a
+ pre snapshot capturing the state of the file system before
+ the start of the module, and a post snapshot after the module
+ has been finished.
+ You can undo the changes made by &yast; and &zypper; by using the &snapper;
+ module in &yast; or the snapper command-line tool. Both allow
+ restoring files from pre snapshots. When comparing two
+ snapshots, the tools show which files were changed. You can also
+ display the differences between two versions of a file (diff).
+
+
+
+
+ Undoing changes using the &snapper; module in &yast;
+ To undo changes with the &snapper; module in &yast;, follow these steps:
+
+
+ Undoing changes using the &yast; <guimenu>Snapper</guimenu> module
+
+
+ Open the Miscellaneous section in &yast; or enter the command
+ yast2 snapper to open it, and start the Filesystem
+ Snapshots module.
+
+
+
+
+ Make sure Current Configuration is set to
+ root. This is always the case unless you have manually
+ added own &snapper; configurations.
+
+
+
+
+ Choose a pair of pre and post snapshots
+ from the list. Both &yast; and &zypper; snapshot pairs are of the type
+ Pre & Post. &yast; snapshots are labeled as
+ zypp(y2base) in the Description column;
+ &zypper; snapshots are labeled zypp(zypper).
+
+
+
+
+
+
+
+
+
+
+ Start the &snapper; module in &yast; and listing snapshots
+
+
+
+
+
+
+ Click Show Changes to open the list of files that
+ differ between the two snapshots.
+
+
+
+
+
+
+
+
+
+
+ Show list of changes in two snapshots in &yast;
+
+
+
+
+
+
+ Review the list of files. To display a diff between the
+ pre and post version of a file,
+ select it from the list.
+
+
+
+
+
+
+
+
+
+ Display diff of pre and post file versions in &yast;
+
+
+
+
+
+
+ To restore one or more files, select the relevant files or directories by
+ activating the respective check box. Click Restore
+ Selected and confirm the action by clicking
+ Yes.
+
+
+
+
+
+
+
+
+
+
+ Restore selected files in &yast;
+
+
+
+
+ To restore a single file, activate its diff view by clicking its name.
+ Click Restore From First and confirm your choice with
+ Yes.
+
+
+
+
+
+
+ Undoing changes using the <command>snapper</command> command
+ To undo changes with the snapper command, follow these steps:
+
+
+ Undoing changes using the <command>snapper</command> command
+
+
+ Get a list of &yast; and &zypper; snapshots by running snapper
+ list -t pre-post. &yast; snapshots are labeled
+ as yast MODULE_NAME in the
+ Description column; &zypper; snapshots are labeled
+ zypp(zypper).
+
+&prompt.sudo;snapper list -t pre-post
+Pre # | Post # | Pre Date | Post Date | Description
+------+--------+-------------------------------+-------------------------------+--------------
+311 | 312 | Tue 06 May 2018 14:05:46 CEST | Tue 06 May 2018 14:05:52 CEST | zypp(y2base)
+340 | 341 | Wed 07 May 2018 16:15:10 CEST | Wed 07 May 2018 16:15:16 CEST | zypp(zypper)
+342 | 343 | Wed 07 May 2018 16:20:38 CEST | Wed 07 May 2018 16:20:42 CEST | zypp(y2base)
+344 | 345 | Wed 07 May 2018 16:21:23 CEST | Wed 07 May 2018 16:21:24 CEST | zypp(zypper)
+346 | 347 | Wed 07 May 2018 16:41:06 CEST | Wed 07 May 2018 16:41:10 CEST | zypp(y2base)
+348 | 349 | Wed 07 May 2018 16:44:50 CEST | Wed 07 May 2018 16:44:53 CEST | zypp(y2base)
+350 | 351 | Wed 07 May 2018 16:46:27 CEST | Wed 07 May 2018 16:46:38 CEST | zypp(y2base)
+
+
+
+ Get a list of changed files for a snapshot pair with snapper
+ status
+ PRE..POST. Files
+ with content changes are marked with c, files that
+ have been added are marked with + and deleted files
+ are marked with -.
+
+&prompt.sudo;snapper status 350..351
++..... /usr/share/doc/packages/mikachan-fonts
++..... /usr/share/doc/packages/mikachan-fonts/COPYING
++..... /usr/share/doc/packages/mikachan-fonts/dl.html
+c..... /usr/share/fonts/truetype/fonts.dir
+c..... /usr/share/fonts/truetype/fonts.scale
++..... /usr/share/fonts/truetype/みかちゃん-p.ttf
++..... /usr/share/fonts/truetype/みかちゃん-pb.ttf
++..... /usr/share/fonts/truetype/みかちゃん-ps.ttf
++..... /usr/share/fonts/truetype/みかちゃん.ttf
+c..... /var/cache/fontconfig/7ef2298fde41cc6eeb7af42e48b7d293-x86_64.cache-4
+c..... /var/lib/rpm/Basenames
+c..... /var/lib/rpm/Dirnames
+c..... /var/lib/rpm/Group
+c..... /var/lib/rpm/Installtid
+c..... /var/lib/rpm/Name
+c..... /var/lib/rpm/Packages
+c..... /var/lib/rpm/Providename
+c..... /var/lib/rpm/Requirename
+c..... /var/lib/rpm/Sha1header
+c..... /var/lib/rpm/Sigmd5
+
+
+
+ To display the diff for a certain file, run snapper
+ diff. It follows this syntax:
+
+ snapper diff PRE..POST [FILENAME]
+
+
+ If you do not specify a
+ FILENAME, a diff for all files will be
+ displayed.
+
+&prompt.sudo;snapper diff 350..351 /usr/share/fonts/truetype/fonts.scale
+--- /.snapshots/350/snapshot/usr/share/fonts/truetype/fonts.scale 2014-04-23 15:58:57.000000000 +0200
++++ /.snapshots/351/snapshot/usr/share/fonts/truetype/fonts.scale 2014-05-07 16:46:31.000000000 +0200
+@@ -1,4 +1,4 @@
+-1174
++1486
+ ds=y:ai=0.2:luximr.ttf -b&h-luxi mono-bold-i-normal--0-0-0-0-c-0-iso10646-1
+ ds=y:ai=0.2:luximr.ttf -b&h-luxi mono-bold-i-normal--0-0-0-0-c-0-iso8859-1
+[...]
+
+
+
+ To restore one or more files, run snapper -v undochange
+ PRE..POST
+ FILENAME. If you do not specify a
+ FILENAME, all the changed files will be restored.
+
+&prompt.sudo;snapper -v undochange 350..351
+create:0 modify:13 delete:7
+undoing change...
+deleting /usr/share/doc/packages/mikachan-fonts
+deleting /usr/share/doc/packages/mikachan-fonts/COPYING
+deleting /usr/share/doc/packages/mikachan-fonts/dl.html
+deleting /usr/share/fonts/truetype/みかちゃん-p.ttf
+deleting /usr/share/fonts/truetype/みかちゃん-pb.ttf
+deleting /usr/share/fonts/truetype/みかちゃん-ps.ttf
+deleting /usr/share/fonts/truetype/みかちゃん.ttf
+modifying /usr/share/fonts/truetype/fonts.dir
+modifying /usr/share/fonts/truetype/fonts.scale
+modifying /var/cache/fontconfig/7ef2298fde41cc6eeb7af42e48b7d293-x86_64.cache-4
+modifying /var/lib/rpm/Basenames
+modifying /var/lib/rpm/Dirnames
+modifying /var/lib/rpm/Group
+modifying /var/lib/rpm/Installtid
+modifying /var/lib/rpm/Name
+modifying /var/lib/rpm/Packages
+modifying /var/lib/rpm/Providename
+modifying /var/lib/rpm/Requirename
+modifying /var/lib/rpm/Sha1header
+modifying /var/lib/rpm/Sigmd5
+undoing change done
+
+
+
+ Reverting user additions
+
+ We do not recommend reverting user additions via undoing changes with &snapper;.
+ Since certain directories are excluded from snapshots, files belonging to
+ these users will remain in the file system. If a new user is created that
+ has the same user ID as a deleted user, this new user will inherit the
+ files. Therefore, it is strongly recommended to use the &yast;
+ User and Group Management tool to remove users.
+
+
+
+