#+title: grub-btrfsd
#+author: Pascal Jaeger
#+MAN_CLASS_OPTIONS: :section-id "8"

* NAME
grub-btrfsd - An OpenRC daemon to automatically update the grub menu with
#+BEGIN_MAN
.BR grub-btrfs (8)
#+END_MAN
when a new btrfs snapshot is created.

* SYNOPSIS
~grub-btrfsd [-h, --help] [-c, --no-color] [-l, --log-file LOG_FILE] [-r, --recursive] [-s, --syslog] [-t, --timeshift-auto] [-o, --timeshift-old] [-v, --verbose] SNAPSHOTS_DIRS~

* DESCRIPTION
Grub-btrfsd is a shell script which is meant to be run as a daemon.
Grub-btrfsd watches a directory where btrfs-snapshots are created or deleted via inotifywait and runs grub-mkconfig (if grub-mkconfig never ran before since grub-btrfs was installed) or ~/etc/grub.d/41_snapshots-btrfs~ (when grub-mkconfig ran before with grub-btrfs installed) when something in that directory changes.

* OPTIONS
** ~SNAPSHOTS_DIRS~
This argument specifies the (space separated) paths where grub-btrfsd looks for newly created snapshots and snapshot deletions. It is usually defined by the program used to make snapshots.
E.g. for Snapper this would be ~/.snapshots~. It is possible to define more than one directory here, all directories will inherit the same settings (recursive etc.).
This argument is not necessary to provide if ~--timeshift-auto~ is set.

** ~-c / --no-color~
Disable colors in output.

** ~-l / --log-file~
This arguments specifies a file where grub-btrfsd should write log messages.

** ~-r / --recursive~
Watch snapshot directory recursively

** ~-s / --syslog~
Write to syslog

** ~-t / --timeshift-auto~
This is a flag to activate the auto detection of the path where Timeshift stores snapshots. Newer versions (>=22.06) of Timeshift mount their snapshots to ~/run/timeshift/$PID/backup/timeshift-btrfs~. Where ~$PID~ is the process ID of the currently running Timeshift session. The PID is changing every time Timeshift is opened. grub-btrfsd can automatically take care of the detection of the correct PID and directory if this flag is set. In this case the argument ~SNAPSHOTS_DIRS~ has no effect.

** ~-o / --timeshift-old~
Look for snapshots in ~/run/timeshift/backup/timeshift-btrfs~ instead of ~/run/timeshift/$PID/backup/timeshift-btrfs~. This is to be used for Timeshift versions <22.06.

** ~-v / --verbose~
Let the log of the daemon be more verbose

** ~-h / --help~
Displays a short help message.

* CONFIGURATION
The daemon is usually configured via the file ~/etc/conf.d/grub-btrfsd~ on openrc-init systems and ~sudo systemctl edit --full grub-btrfsd~ on systemd systems. In this file the arguments (See OPTIONS), that OpenRC passes to the daemon when it is started, can be configured.

** NOTES
A common configuration for Snapper would be to set ~SNAPSHOTS_DIR~ to ~/.snapshots~ and not to set ~--timeshift-auto~.
For Timeshift ~--timeshift-auto~ is set to true and ~SNAPSHOTS_DIR~ can be left as is.

* FILES
~/etc/conf.d/grub-btrfsd~
~/usr/lib/systemd/system/grub-btrfsd.service~

* SEE ALSO
#+BEGIN_MAN
.IR btrfs (8)
.IR btrfs-subvolume (8)
.IR grub-btrfsd (8)
.IR grub-mkconfig (8)
.IR inotifywait (1)
.IR openrc (8)
.IR rc-service (8)
.IR timeshift (1)
#+END_MAN

* COPYRIGHT
Copyright (c) 2022 Pascal Jäger