---
name: "ssh_filter_btrbk"
section: "1"
platform: "linux"
package: "btrbk"
version: "0.32.7-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/ssh_filter_btrbk"
---

# ssh\_filter\_btrbk(1)

ssh command filter script for btrbk

## NAME

ssh\_filter\_btrbk - ssh command filter script for btrbk

## SYNOPSIS

```
ssh_filter_btrbk.sh [-s|--source] [-t|--target] [-d|--delete]
    [-i|--info] [--snapshot] [--send] [--receive]
    [-p|--restrict-path <path>] [-l|--log] [--sudo]
```

## DESCRIPTION

**ssh\_filter\_btrbk.sh** restricts SSH commands to commands used by *btrbk*. It examines the SSH\_ORIGINAL\_COMMAND environment variable (set by sshd) and executes it only if it contains commands used by *btrbk*.

The accepted commands are specified by the "--source", "--target", "--delete" and "--info" options.

The following commands are always allowed:

• "btrfs subvolume show" (not affected by "--restrict-path")

• "btrfs subvolume list" (not affected by "--restrict-path")

• "readlink"

• "test -d" (only if "compat busybox" configuration option is set)

• "cat /proc/self/mountinfo"

• pipes through "gzip", "pigz", "bzip2", "pbzip2", "bzip3", "xz", "lzop", "lz4", "zstd" (stream\_compress)

• pipes through "mbuffer" (stream\_buffer, rate\_limit)

Example line in /root/.ssh/authorized\_keys on a backup target host:

```
command="ssh_filter_btrbk.sh --target --delete --restrict-path /mnt/btr_backup",restrict ssh-rsa AAAAB3NzaC1...hwumXFRQBL btrbk@example.org
```

## OPTIONS

- \-s, --source

  Allow commands for backup source: "btrfs subvolume snapshot", "btrfs send". Equivalent to "--snapshot --send".

- \-t, --target

  Allow commands for backup and archive target: "btrfs receive", "mkdir".

- \-d, --delete

  Allow commands for subvolume deletion: "btrfs subvolume delete". This is used for backup source if *snapshot\_preserve\_daily* is not set to “all”, and for backup targets if *target\_preserve\_daily* is not set to “all”.

- \-i, --info

  Allow informative commands: "btrfs subvolume find-new", "btrfs filesystem usage". This is used by btrbk *info* and *diff* commands.

- \--snapshot

  Allow btrfs snapshot command: "btrfs subvolume snapshot".

- \--send

  Allow btrfs send command: "btrfs send".

- \--receive

  Allow btrfs receive command: "btrfs receive".

- \-p, --restrict-path \<path\>

  Restrict commands to \<path\>. Note that "btrfs subvolume show", "btrfs subvolume list" are NOT affected by this option.

  It is not possible to restrict commands to exact subvolume names, as [btrfs-receive(8)](/btrfs-receive/8.md) takes a \<path\> as argument (directory, not including the subvolume file name to be created, this is encoded in the send-stream).

- \-l, --log

  Log ACCEPT and REJECT messages to the system log.

- \--sudo

  Allow btrfs commands to be called via sudo. Enable this if you have "backend btrfs-progs-sudo" in your btrbk configuration file.

## AVAILABILITY

Please refer to the btrbk project page  **\<https://digint.ch/btrbk/\>** *for further details.*

## SEE ALSO

**btrbk***(1),* **btrbk.conf***(5),* **btrfs***(8)*

## AUTHOR

*Axel Burri*  *\<axel@tty0.ch\>*