Timepatrol is a BTRFS snapshot manager and a rollback tool in a single script. There are great tools out there which do the same, like Timeshift and Snapper, for example, but I still prefer Timepatrol because:

• Easy to rollback to any snapshot.
• Minimal dependency: ruby.
• Outputs fit in half screen. Perfect for window manager users.
• It has colors! Although it can be disabled.

In fact, it was written based on my personal needs but it may be of interest of a few people also.

In principle it can be used in any Linux distribution. Arch users will benefit from the pacman pre and post hooks which I found to be very handy in the day-to-day use.

• ruby

From AUR, which I maintain myself.

1. git clone https://github.com/abdeoliveira/timepatrol
2. cd timepatrol
3. sudo ./install.sh

sudo pacman -Rs timepatrol-git

sudo rm -r /usr/bin/timepatrol /etc/timepatrol

Copy the example configuration file as

sudo cp /etc/timepatrol/config-example /etc/timepatrol/config

Then, check the comments in config file for directions and adjust it as per your system.

Once you have finished, I recommend you run sudo timepatrol check to see if timepatrol spots any misconfiguration.

A note regarding /etc/fstab: The default installation in some distributions (Arch for instance) include the subvolid information in fstab for mounting points. Since rollbacks change such a number I recommend you omit the subvolid in the / entry. Mine reads as follows:

# Static information about the filesystems.
# See fstab(5) for details.

# <file system> <dir> <type> <options> <dump> <pass>
# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/         	btrfs     	rw,relatime,ssd,space_cache=v2,subvol=/@	0 0

# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/home     	btrfs     	rw,relatime,ssd,space_cache=v2,subvolid=257,subvol=/@home	0 0

# /dev/mapper/ainstnvme0n1p2
UUID=054b4420-a2e0-41b1-8d66-8cc7198d8b55	/var/log  	btrfs     	rw,relatime,ssd,space_cache=v2,subvolid=258,subvol=/@log	0 0

...

Type sudo timepatrol help for a basic list of commands. They are

• check: checks the configuration file and simulates (dryrun) a rollback.

• list: lists snapshots limiting shown comment characters.

• list-verbose: lists snapshots without limiting comment characters.

• list-grep 'STRING': lists snapshots containning STRING in comments.

• snapshot 'OPTIONAL COMMENT': takes a snapshot of / with (optional) given comment.

• snapshot-keep 'OPTIONAL COMMENT': same as above plus it adds a protection against automatic deletion. Automatic deletion is set via the MAXIMUM_SNAPSHOTS variable in the /etc/timepatrol/config file. Protected snapshots have a * mark next to their IDs, and they do not count against the MAXIMUM_SNAPSHOTS variable. For example, if 2 snapshots are protected and MAXIMUM_SNAPSHOTS = 20, then the maximum number of snapshots will be 22.

• change-comment ID 'NEW COMMENT': replaces current COMMENT of snapshot ID by 'NEW COMMENT'.

• delete: deletes a snapshot. It accepts individual ID numbers and ranges. For example: sudo timepatrol delete 1,10,20-23 will delete snapshots whose IDs are 1, 10, 20, 21, 22, and 23. The delete command also accepts the following substring selectors: date=, time=, kernel=, and comment=. See the example of usage below:

oliveira@arch:~$ sudo timepatrol delete time=16:
*[208]  2024.08.12  16:30:05  6.10.4-arch2-1  Niri OK 
 [258]  2024.08.20  16:07:01  6.10.5-arch1-1  PRE: install libxp (1.0.4-3) 
 [259]  2024.08.20  16:07:56  6.10.5-arch1-1  PRE: remove libxp (1.0.4-3) 
 [260]  2024.08.20  16:26:31  6.10.5-arch1-1  PRE: install libxp (1.0.4-3), install 
                                              openmotif (2.3.8-3), install t1lib 
                                              (5.1.2-8) 
 [264]  2024.08.21  10:16:52  6.10.6-arch1-1  PRE: upgrade timepatrol-git 
                                              (r149.7e4bff6-1 -> r151.3f4f304-1) 
:: Confirm deletion of the selected snapshot(s) above? [y/N]

Note that all snapshots containing the user-given substring 16: in the time field were selected for deletion. I recommend you play with the other selectors. In any case, the user will always be prompted to confirm the deletion with the No answer being the defaut.

• toggle-keep: Toggles between protect and unprotect snapshots. It accepts an individul ID, list of IDs, ranges and selectors similar to the delete command above.

• rollback: rolls back the installation to a previous, selected snapshot state. Some notes:

(i) rolling back to a snapshot whose kernel is different from the running kernel is not allowed (the script will ABORT). You must adjust the current kernel (downgrade/upgrade), then reboot (so it is loaded), then try to rollback.

(ii) Plese read the recommendation regarding the /etc/fstab file before rollback.

(iii) Reboot immediately after kernel upgrade. To be on the safe side, reboot immediately after any system upgrade. See the Troubleshooting section also.

1. Install bash-completion

2. Logout and login, or reboot.

1. Install bash-completion

2. Copy and paste the contents of completions/timepatrol to your ~/.bashrc:

cat completions/timepatrol >> ~/.bashrc

3. Logout and login, or reboot.

For a 24/7 running machine, probably the simplest way is setting a cronjob as root.

For notebooks, I recommend simplecron, which I mantain myself.

Several factors can lead to an unbootable system after a rollback. For instance, if you upgraded the kernel but didn't reboot before rolling back, your system might fail to start.

While I can't cover every possible system recovery scenario, the following steps should help in many cases:

1. Boot from a live media.
2. Chroot into your (broken) system.
3. Mount all partitions (e.g., mount -a).
4. Regenerate the initramfs (mkinitcpio -P for Arch, or the equivalent for your distro).
5. If the issue persists, try downgrading the kernel. On Arch, pacman generally handles this well.
6. Exit chroot and reboot.