$ yay -S community/restic
resolving dependencies...
looking for conflicting packages...

Packages (1) restic-0.14.0-1

Total Download Size:    6.65 MiB
Total Installed Size:  23.28 MiB

:: Proceed with installation? [Y/n] 
:: Retrieving packages...
 restic-0.14.0-1-x86_64                         6.7 MiB  15.8 MiB/s 00:00 [#########################################] 100%
(1/1) checking keys in keyring                                            [#########################################] 100%
(1/1) checking package integrity                                          [#########################################] 100%
(1/1) loading package files                                               [#########################################] 100%
(1/1) checking for file conflicts                                         [#########################################] 100%
(1/1) checking available disk space                                       [#########################################] 100%
:: Processing package changes...
(1/1) installing restic                                                   [#########################################] 100%
Optional dependencies for restic
    fuse2: mount archive [installed]
:: Running post-transaction hooks...
(1/1) Arming ConditionNeedsUpdate...

$ ssh-keygen

$ ssh-copy-id -s -p23 $user@$user.your-storagebox.de
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/root/.ssh/id_rsa.pub"
/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed
/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keys
$user@$user.your-storagebox.de's password: 
sftp> -get .ssh/authorized_keys /root/.ssh/ssh-copy-id.lGCBvKFFJS7/authorized_keys
sftp> -mkdir .ssh
remote mkdir "/home/.ssh": Failure
sftp> chmod 700 .ssh
sftp> put /root/.ssh/ssh-copy-id.lGCBvKFFJS7/authorized_keys .ssh/authorized_keys
sftp> chmod 600 .ssh/authorized_keys

Number of key(s) added: 1

Now try logging into the machine, with:   "sftp -p '23' '$user@$user.your-storagebox.de'"
and check to make sure that only the key(s) you wanted were added.

$ ssh -p23 $user@$user.your-storagebox.de
Last login: Sun Nov 27 20:05:01 2022 from 2a02:8109:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
+------------------------------------------------------------------+
| Welcome to your Storage Box.                                     |
|                                                                  |
| Please note that this is only a restricted shell environment and |
| therefore some shell features like pipes and redirects are not   |
| supported.                                                       |
+------------------------------------------------------------------+
$user /home > exit

$ restic -r sftp://$user@[$user.your-storagebox.de]:23/restic init
enter password for new repository: 
enter password again: 
created restic repository cc911a5e39 at sftp://$user@[$user.your-storagebox.de]:23/restic

Please note that knowledge of your password is required to access
the repository. Losing your password means that your data is
irrecoverably lost.

$ mkdir ~/bin
$ cat ~/bin/backup.sh
#!/bin/bash
export RESTIC_PASSWORD=XXX

restic --tag homeassistant -q -r sftp://$user@[$user.your-storagebox.de]:23/restic backup /home/homeassistant/ha/homeassistant/backups

$ chmod +x ~/bin/backup.sh
$ crontab -l
@daily /usr/bin/bash /home/homeassistant/bin/backup.sh >/dev/null 2>&1

$ ~/bin/backup.sh
$ restic -r sftp://$user@[$user.your-storagebox.de]:23/restic snapshots
enter password for repository: 
repository cc911a5e opened (repository version 2) successfully, password is correct
ID        Time                 Host             Tags           Paths
-----------------------------------------------------------------------------------------------------------
007457e3  2022-11-27 21:59:32  helium           homeassistant  /home/homeassistant/ha/homeassistant/backups
-----------------------------------------------------------------------------------------------------------
1 snapshot