`dar-backup`

Reliable DAR backups, automated in clean Python

_{🎯 Stats powered by ClonePulse}

The wonderful 'dar' Disk Archiver is used for the heavy lifting, together with the parchive suite in these scripts.

This is the Python based version 2 of dar-backup.

You can see the v2 Changelog for details on features and progress.

TL;DR

dar-backup is a Python-powered CLI for creating and validating full, differential, and incremental backups using dar and par2. Designed for long-term restore integrity, even on user-space filesystems like FUSE.

Version 1.0.0 was reached on October 9, 2025.

High-level flow

Quick links

Quick Guide
Redundancy to fix bitrot
Point In Time Recovery
550+ unit tests & integration tests
- par2 bitrot repair proof, full/diff/incr with restore, PITR verifications, ...

My use case

I needed the following:

Backup my workstation to a remote server
Backup primarily photos, home made video and different types of documents
I have cloud storage mounted on a directory within my home dir. The filesystem is FUSE based, which gives it a few special features
- Backup my cloud storage (cloud is convenient, but I want control over my backups)
- A non-privileged user can perform a mount
- A privileged user cannot look into the filesystem --> a backup script running as root is not suitable
Have a simple way of restoring, possibly years into the future. 'dar' fits that scenario with a single statically linked binary (kept with the archives). There is no need install/configure anything - restoring is simple and works well.
During backup archives must be tested and a restore test (however small) performed
Archives stored on a server with a reliable file system (easy to mount a directory over sshfs)
Easy to verify archive's integrity, after being moved around.

I do not need the encryption features of dar, as all storage is already encrypted.

My setup

Primary backup to server with an ext4 file system on mdadm RAID1
Secondary copies to multiple USB disks / cloud
Archive integrity verification anywhere using Par2 and dar -t.
Archive repair anywhere if needed. By default dar-backup creates par2 redundancy files with 5% coverage. Enough to fix localized bitrot.
No dependency on original system

Why PAR2 is especially good for portable / offsite copies

PAR2 parity is:

Self-contained (travels with the data)

Format-agnostic (works on any filesystem)

Location-agnostic (local disk, USB, cloud object storage)

Tool-stable (PAR2 spec has not changed in years)

That means:

Integrity protection moves with the archive.

Design choices

My design choices are boring, proven and pragmatic:

mdadm handles disks

PAR2 handles data integrity

You control when and how verification happens

Errors have a fair chance of being diagnosed and fixed, due to well known tooling.

No hidden magic, no lock-in

Features

The battle tested dar Disk Archiver is used for the actual backups - it comes highly recommended.
Backup with test of backup and (configurable) restore tests of files with comparison to source
Redundancy files created for patching bitrot of the archives (size configurable)
Simple backup definitions defining what to backup (as many as you need)
Backup catalogs in databases, optionally on a disk different from the backups
Flexible and precise logging
Bash and zsh shell autocompletion for a nice CLI experience, available completions:
- Options for dar-backup, cleanup, manager
- Backup definitions
- Archives - filtered to backup definition if given
- Catalogs - filtered to backup definition if given
dar-backup is easy to install and configure.
✅ The author has used dar-backup since > 4 years, and has been saved multiple times.

License

These scripts are licensed under the GPLv3 license. Read more here: GNU GPL3.0, or have a look at the "LICENSE" file in this repository.

Quick Guide

This purpose of this quick guide is to show how dar-backup works in a few simple steps.

The package include a demoapplication, that can help you set up dar-backup quickly.

⚠️ Assumption

The demo program uses these directories in your home directory:

$HOME/dar-backup

$HOME/.config/dar-backup

It is assumed they do not exist before running the demo.

Python >= 3.11 is required

Let's roll with installation, backup, list backup content, restore & restore check

The demo is known to work on an Ubuntu 24.04 clean VM as delivered from Multipass

sudo apt -y install dar par2 python3 python3-venv
INSTALL_DIR=/tmp/dar-backup
mkdir "$INSTALL_DIR"
cd "$INSTALL_DIR"
python3 -m venv venv    # create the virtual environment 
. venv/bin/activate     # activate the virtual environment
pip install dar-backup  # run pip to install `dar-backup` into the virtual environment

🎯 Install details

(venv) $ INSTALL_DIR=/tmp/dar-backup
mkdir "$INSTALL_DIR"
cd "$INSTALL_DIR"
python3 -m venv venv    # create the virtual environment 
. venv/bin/activate     # activate the virtual environment
pip install dar-backup  # run pip to install `dar-backup`
Collecting dar-backup
  Downloading dar_backup-0.6.21-py3-none-any.whl.metadata (88 kB)
     ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 88.5/88.5 kB 3.7 MB/s eta 0:00:00
Collecting argcomplete>=3.6.2 (from dar-backup)
  Using cached argcomplete-3.6.2-py3-none-any.whl.metadata (16 kB)
Collecting inputimeout>=1.0.4 (from dar-backup)
  Using cached inputimeout-1.0.4-py3-none-any.whl.metadata (2.2 kB)
Collecting rich>=13.0.0 (from dar-backup)
  Using cached rich-14.0.0-py3-none-any.whl.metadata (18 kB)
Collecting markdown-it-py>=2.2.0 (from rich>=13.0.0->dar-backup)
  Using cached markdown_it_py-3.0.0-py3-none-any.whl.metadata (6.9 kB)
Collecting pygments<3.0.0,>=2.13.0 (from rich>=13.0.0->dar-backup)
  Using cached pygments-2.19.1-py3-none-any.whl.metadata (2.5 kB)
Collecting mdurl~=0.1 (from markdown-it-py>=2.2.0->rich>=13.0.0->dar-backup)
  Using cached mdurl-0.1.2-py3-none-any.whl.metadata (1.6 kB)
Downloading dar_backup-0.6.21-py3-none-any.whl (101 kB)
   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 101.9/101.9 kB 16.2 MB/s eta 0:00:00
Using cached argcomplete-3.6.2-py3-none-any.whl (43 kB)
Using cached inputimeout-1.0.4-py3-none-any.whl (4.6 kB)
Using cached rich-14.0.0-py3-none-any.whl (243 kB)
Using cached markdown_it_py-3.0.0-py3-none-any.whl (87 kB)
Using cached pygments-2.19.1-py3-none-any.whl (1.2 MB)
Using cached mdurl-0.1.2-py3-none-any.whl (10.0 kB)
Installing collected packages: pygments, mdurl, inputimeout, argcomplete, markdown-it-py, rich, dar-backup
Successfully installed argcomplete-3.6.2 dar-backup-0.6.21 inputimeout-1.0.4 markdown-it-py-3.0.0 mdurl-0.1.2 pygments-2.19.1 rich-14.0.0

Setup the demo configurations and show a few operations

# See reference section for options tweaking the install
demo --install

# create catalog database
manager --create-db

# FULL backup as defined in backup definition `demo`
dar-backup --full-backup  

# List the contents of the backup
dar-backup --list-contents demo_FULL_$(date '+%F')

🎯 --list details

(venv) $ demo --install
Directories created.
File generated at '/home/user/.config/dar-backup/backup.d/demo'
File generated at '/home/user/.config/dar-backup/dar-backup.conf'
1. Now run `manager --create-db` to create the catalog database.
2. Then you can run `dar-backup --full-backup` to create a backup.
3. List backups with `dar-backup --list`
4. List contents of a backup with `dar-backup --list-contents <backup-name>`



(venv) $ manager --create-db 
========== Startup Settings ==========
manager.py:     0.7.1
Config file:    /home/user/.config/dar-backup/dar-backup.conf
Logfile:        /home/user/dar-backup/dar-backup.log
dar_manager:    /home/user/.local/dar/bin/dar_manager
dar_manager v.: 1.9.0
======================================



(venv) $ dar-backup --full-backup
========== Startup Settings ==========
dar-backup.py:    0.7.1
dar path:         /home/user/.local/dar/bin/dar
dar version:      2.7.17
Script directory: /home/user/git/dar-backup/v2/src/dar_backup
Config file:      /home/user/.config/dar-backup/dar-backup.conf
.darrc location:  /home/user/git/dar-backup/v2/src/dar_backup/.darrc
======================================



(venv) $ dar-backup --list-contents demo_FULL_$(date '+%F')
========== Startup Settings ==========
dar-backup.py:    0.7.1
dar path:         /home/user/.local/dar/bin/dar
dar version:      2.7.17
Script directory: /home/user/git/dar-backup/v2/src/dar_backup
Config file:      /home/user/.config/dar-backup/dar-backup.conf
.darrc location:  /home/user/git/dar-backup/v2/src/dar_backup/.darrc
======================================
[Saved][-]       [-L-][  49%][ ]  drwx------   user user  8 kio Sat May 17 13:13:59 2025  .config
[Saved][-]       [-L-][  49%][ ]  drwxrwxr-x   user user  8 kio Tue May  6 20:55:40 2025  .config/dar-backup
[Saved][-]       [-L-][  48%][ ]  drwxrwxr-x   user user  6 kio Sat May 17 13:26:21 2025  .config/dar-backup/backup.d
[Saved][ ]       [-L-][  40%][ ]  -rw-rw-r--   user user  764 o Sun Feb 23 21:23:01 2025  .config/dar-backup/backup.d/media-files
[Saved][ ]       [-L-][  41%][ ]  -rw-rw-r--   user user  933 o Sun Feb 23 21:23:15 2025  .config/dar-backup/backup.d/pCloudDrive
[Saved][ ]       [-L-][  48%][ ]  -rw-rw-r--   user user  1 kio Sun Mar 16 10:40:29 2025  .config/dar-backup/backup.d/test
[Saved][ ]       [-L-][  48%][ ]  -rw-rw-r--   user user  824 o Tue May 13 17:00:52 2025  .config/dar-backup/backup.d/default
[Saved][ ]       [-L-][  48%][ ]  -rw-rw-r--   user user  1 kio Sat May  3 10:40:33 2025  .config/dar-backup/backup.d/user-homedir
[Saved][ ]       [-L-][  54%][ ]  -rw-rw-r--   user user  1 kio Sat May 17 18:17:40 2025  .config/dar-backup/backup.d/demo
[Saved][ ]       [-L-][  55%][ ]  -rw-rw-r--   user user  1 kio Sat May 17 18:17:40 2025  .config/dar-backup/dar-backup.conf

Perform a restore and show the restored files

# Restore all files in the backup
dar-backup --restore demo_FULL_$(date '+%F') --verbose

# Prove the files have been restored to directory as configured
find $HOME/dar-backup/restore

🎯 --restore details

(venv) $ dar-backup --restore demo_FULL_$(date '+%F') --verbose
========== Startup Settings ==========
dar-backup.py:    0.7.1
dar path:         /home/user/.local/dar/bin/dar
dar version:      2.7.17
Script directory: /home/user/git/dar-backup/v2/src/dar_backup
Config file:      /home/user/.config/dar-backup/dar-backup.conf
.darrc location:  /home/user/git/dar-backup/v2/src/dar_backup/.darrc
Backup.d dir:     /home/user/.config/dar-backup/backup.d
Backup dir:       /home/user/dar-backup/backups
Restore dir:      /home/user/dar-backup/restore
Logfile location: /home/user/dar-backup/dar-backup.log
PAR2 enabled:     True
--do-not-compare: False
======================================



(venv) $ find ~/dar-backup/restore/
/home/user/dar-backup/restore/
/home/user/dar-backup/restore/.config
/home/user/dar-backup/restore/.config/dar-backup
/home/user/dar-backup/restore/.config/dar-backup/backup.d
/home/user/dar-backup/restore/.config/dar-backup/backup.d/media-files
/home/user/dar-backup/restore/.config/dar-backup/backup.d/pCloudDrive
/home/user/dar-backup/restore/.config/dar-backup/backup.d/test
/home/user/dar-backup/restore/.config/dar-backup/backup.d/default
/home/user/dar-backup/restore/.config/dar-backup/backup.d/user-homedir
/home/user/dar-backup/restore/.config/dar-backup/backup.d/demo
/home/user/dar-backup/restore/.config/dar-backup/dar-backup.conf

✅ Next steps

Play with demo's options:

--root-dir (perhaps $HOME)

--dir-to-backup (perhaps Pictures)

--backup-dir (perhaps /media/user/big-disk)

See log file: cat "$HOME/dar-backup/dar-backup.log"

Checkout systemd timers and services

Checkout shell autocompletion (very nice !)

Checkout the reference section

Status

1.0.0 milestone reached

October 9, 2025, I have promoted version 0.8.4 --> 1.0.0 after having added more test cases and seen no issues with 0.8.4.

As of February 13, 2025, I have changed the status from alpha --> beta, as the featureset is in place and the alphas have worked well for a very long time.

As of August 8, 2024 I am using the alpha versions of dar-backup (alpha-0.5.9 onwards) in my automated backup routine.

GPG Signing key

To increase the security and authenticity of dar-backup packages, all releases from v2-beta-0.6.18 onwards will be digitally signed using the GPG key below.

🎯 GPG Signing Key Details

Name:        Per Jensen (author of dar-backup)
Email:       dar-backup@pm.me
Primary key: 4592 D739 6DBA EFFD 0845  02B8 5CCE C7E1 6814 A36E
Signing key: B54F 5682 F28D BA36 22D7  8E04 58DB FADB BBAC 1BB1
Created:     2025-03-29
Expires:     2030-03-28
Key type:    ed25519 (primary, SC)  
Subkeys:     ed25519 (S), ed25519 (A), cv25519 (E)

🎯 Where to Find Release Signatures

PyPI does Not host .asc Signature Files

Although the dar-backup packages on PyPI are GPG-signed, PyPI itself does not support uploading .asc detached signature files alongside .whl and .tar.gz artifacts.

Therefore, you will not find .asc files on PyPI.

Where to Get .asc Signature Files

You can always download the signed release artifacts and their .asc files from the official GitHub Releases page:

📁 GitHub Releases for dar-backup

Each release includes:

dar_backup-x.y.z.tar.gz
dar_backup-x.y.z.tar.gz.asc
dar_backup-x.y.z-py3-none-any.whl
dar_backup-x.y.z-py3-none-any.whl.asc

🎯 How to Verify a Release from GitHub

Import the GPG public key:

curl https://keys.openpgp.org/vks/v1/by-fingerprint/4592D7396DBAEFFD084502B85CCEC7E16814A36E | gpg --import

Download the wheel or tarball and its .asc signature from the GitHub.

Run GPG to verify it:

gpg --verify dar_backup-x.y.z.tar.gz.asc dar_backup-x.y.z.tar.gz
# or
gpg --verify dar_backup-x.y.z-py3-none-any.whl.asc dar_backup-x.y.z-py3-none-any.whl

If the signature is valid, you'll see:

gpg: Good signature from "Per Jensen (author of dar-backup) <dar-backup@pm.me>"

🛡️ Reminder: Verify the signing subkey

Only this subkey is used to sign PyPI packages:

B54F 5682 F28D BA36 22D7  8E04 58DB FADB BBAC 1BB1

You can view it with:

gpg --list-keys --with-subkey-fingerprints dar-backup@pm.me

Homepage - Github

'dar-backup' package lives here: Github - dar-backup

This python version is v2 of dar-backup, v1 is made in bash.

Community

Please review the Code of Conduct to help keep this project welcoming and focused.

Requirements

A linux system
dar
parchive (par2)
python3
python3-venv

On Ubuntu, install the requirements this way:

    sudo apt install dar par2 python3 python3-venv

dar-backup principles

dar-backup overview

dar-backup

dar-backup is built in a way that emphasizes getting backups. It loops over the backup definitions, and in the event of a failure while backing up a backup definition, dar-backup shall log an error and start working on the next backup definition.

There are 3 levels of backups, FULL, DIFF and INCR.

The author does a FULL yearly backup once a year. This includes all files in all directories as defined in the backup definition(s) (assuming -d was not given).
The author makes a DIFF once a month. The DIFF backs up new and changed files compared to the FULL backup.
- No DIFF backups are taken until a FULL backup has been taken for a particular backup definition.
The author takes an INCR backup every 3 days. An INCR backup includes new and changed files compared to the DIFF backup.
- So, a set of INCR's will contain duplicates (this might change as I become more used to use the catalog databases)
- No INCR backups are taken until a DIFF backup has been taken for a particular backup definition.

After each backup of a backup definition, dar-backup tests the archive and then performs a few restore operations of random files from the archive (see dar-backup.conf). The restored files are compared to the originals to check if the restore went well.

dar-backup skips doing a backup of a backup definition if an archive is already in place. So, if you for some reason need to take a new backup on the same date, the first archive must be deleted (I recommend using cleanup).

cleanup

The cleanup application deletes DIFF and INCR if the archives are older than the thresholds set up in the configuration file.

cleanup will only remove FULL archives if the option --cleanup-specific-archives is used. It requires the user to confirm deletion of FULL archives.

Use --dry-run to preview which archives, PAR2 files, and catalogs would be removed without deleting anything.

Examples:

cleanup --dry-run -d media-files --log-stdout
cleanup --dry-run --cleanup-specific-archives -d media-files media-files_INCR_2025-12-22

manager

darhas the concept of catalogs which can be exported and optionally be added to a catalog database. That database makes it much easier to restore the correct version of a backed up file if for example a target date has been set.

dar-backup adds archive catalogs to their databases (using the manager script). Should the operation fail, dar-backup logs an error and continue with testing and restore validation tests.

How to run

📦 All official dar-backup releases from v2-beta-0.6.18 are signed with GPG.

See more here.

1 - installation

Installation is currently in a virtual environment (commonly called a venv). These commands are installed in the venv:

dar-back
cleanup
manager
clean-log
dar-backup-systemd
installer
demo

Note:

The modules inputimeout, richand argcomplete are installed into the venv and used by dar-backup

To install dar-backup, create a venv and run pip:

mkdir $HOME/tmp
cd $HOME/tmp
python3 -m venv venv    # create the virtual environment 
. venv/bin/activate     # activate the virtual environment
pip install dar-backup  # run pip to install `dar-backup`

I have an alias in ~/.bashrc pointing to my venv:

alias db=". ~/tmp/venv/bin/activate; dar-backup -v"

drop the alias into ~/.bashrc like this:

grep -qxF 'alias db="' ~/.bashrc \
  || echo 'alias db=". ~/tmp/venv/bin/activate; dar-backup -v"' >> ~/.bashrc

source ~/.bashrc

Typing db at the command line gives something like this:

(venv) user@machine:~$ db
dar-backup 0.6.12
dar-backup.py source code is here: https://github.com/per2jensen/dar-backup
Licensed under GNU GENERAL PUBLIC LICENSE v3, see the supplied file "LICENSE" for details.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY APPLICABLE LAW, not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
See section 15 and section 16 in the supplied "LICENSE" file.

2 - configuration

The dar-backup installer application can be used to setup the needed directories for dar-backup to work. It creates necessary directories as prescribed in the config file and optionally creates manager databases.

installer can also add configuration of shell auto completion.

Step 1:

Create a config file - see details on config file)

Step 2:

Create one or more backup definitions - see details on backup definitions

Step 3:

Run the installer:

installer --config <path to dar-backup.conf> --install-autocompletion

3 - generate catalog databases

Generate the archive catalog database(s).

dar-backup expects the catalog databases to be in place, it does not automatically create them (by design)

manager --create-db

4 - give dar-backup a spin

You are now ready to do backups as configured in your backup definition(s).

Give dar-backupa spin:

dar-backup --full-backup --verbose

# list backups
dar-backup --list

# list contents of a dar backup
dar-backup --list-contents <TAB>... <choose a backup>

# see some examples on usage
dar-backup --examples

# see the log file
cat "$HOME/dar-backup/dar-backup.log"

If you want to see dar-backup's log entries in the terminal, use the --log-stdout option.

If you want more log messages, use the --verbose or --log-level debug for even more.

If you want to take a backup using a single backup definition, use the -d <backup definition> option. The backup definition's name is the filename of the definition in the BACKUP.D_DIR (see config file).

dar-backup --full-backup -d <your backup definition>

5 - deactivate venv

Deactivate the virtual environment (venv).

deactivate

Config

Config file

The configuration file's default location is: ~/.config/dar-backup/dar-backup.conf

If you have your config file somewhere else, use the --config-file option to point to it.

Tilde ~ and environment variables can be used in the paths for various file locations.

[MISC]
LOGFILE_LOCATION=~/.dar-backup.log
# optional parameters
# LOGFILE_MAX_BYTES = 26214400  # 25 MB max file size is default, change as neeeded
# LOGFILE_BACKUP_COUNT = 5      # 5 backup log files is default, change as needed
MAX_SIZE_VERIFICATION_MB = 20
MIN_SIZE_VERIFICATION_MB = 1
NO_FILES_VERIFICATION = 5
# timeout in seconds for backup, test, restore and par2 operations
# The author has such `dar` tasks running for 10-15 hours on the yearly backups, so a value of 24 hours is used.
# If a timeout is not specified when using the util.run_command(), a default timeout of 30 secs is used.
# Use -1 to disable timeouts.
COMMAND_TIMEOUT_SECS = 86400

[DIRECTORIES]
BACKUP_DIR = /some/where/dar-backup/backups/
BACKUP.D_DIR = /some/where/dar-backup/backup.d
TEST_RESTORE_DIR = /tmp/dar-backup/restore/
# Optional parameter
# If you want to store the catalog databases away from the BACKUP_DIR, use the MANAGER_DB_DIR variable.
#MANAGER_DB_DIR = /some/where/else/

[AGE]
# age settings are in days
# `cleanup` script removes archives and their .par redundancy files if older than configured.
# `cleanup` does not remove FULL archives, unless specifically told to and a "y" is answered to "are you sure?".
DIFF_AGE = 100
INCR_AGE = 40

[PAR2]
ERROR_CORRECTION_PERCENT = 5
ENABLED = True
# Optional PAR2 configuration
# PAR2_DIR = /path/to/par2-store
# PAR2_RATIO_FULL = 10
# PAR2_RATIO_DIFF = 5
# PAR2_RATIO_INCR = 5
# PAR2_RUN_VERIFY = false

# Optional per-backup overrides (section name = backup definition)
[media-files]
PAR2_DIR = /mnt/par2/media-files
PAR2_RATIO_FULL = 10

# scripts to run before the backup to setup the environment
[PREREQ]
SCRIPT_1 = ls -l /tmp
#SCRIPT_2 = another_script.sh

[POSTREQ]
SCRIPT_1 = df -h
#SCRIPT_2 = another_script.sh

PAR2 notes:

If PAR2_DIR is unset, par2 files are created next to the archive slices (legacy behavior) and no manifest is written
When PAR2_DIR is set, dar-backup writes a manifest next to the par2 set: archive_base.par2.manifest.ini
When generating a par2 set, par2 reads all archive slices before writing any output files; for large backups, this initial read can take hours
Verify or repair using: par2 verify -B <archive_dir> <par2_set.par2> par2 repair -B <archive_dir> <par2_set.par2>

.darrc

The package includes a default darrc file which configures dar.

You can override the default .darrc using the --darrc option.

The default .darrc contents are as follows:

#  .darrc configuration file for `dar` as used by the `dar-backup` script.
#  `dar-backup` lives here: https://github.com/per2jensen/dar-backup


##############################################################

#  target: verbose

#  remove comments belov for dar being more verbose

verbose:

# shows files teated due to filtering inclusion or no filtering at all

# -vt

# shows skipped files du to exclusion

# -vs

# shows diretory currently being processed
# dar-backup logs `dar` stdout in real time, so directories being processed are now shown in the log file.
# this is quite useful in long running jobs
 -vd 

# shows detailed messages, not related to files and directories
# -vm

# shows summary of each treated directory, including average compression
# dar-backup logs `dar` stdout in real time, so directories being processed are now shown in the log file.
# this is quite useful in long running jobs
 -vf

# equivalent to "-vm -vs -vt"
# -va


restore-options:
# don't restore File Specific Attributes
#--fsa-scope none

# ignore owner, useful when used by a non-privileged user
--comparison-field=ignore-owner


# Exclude specific file types from compression
compress-exclusion:

# First setting case insensitive mode on:
-an
-ag

-Z    "*.gz"
-Z    "*.bz2"
-Z    "*.xz"
-Z    "*.zip"
-Z    "*.rar"
-Z    "*.7z"
-Z    "*.tar"
-Z    "*.tgz"
-Z    "*.tbz2"
-Z    "*.txz"
# Exclude common image file types from compression
-Z    "*.jpg"
-Z    "*.jpeg"
-Z    "*.png"
-Z    "*.gif"
-Z    "*.bmp"
-Z    "*.tiff"
-Z    "*.svg"
-Z    "*.ico"
-Z    "*.webp"
# The author uses Nikon compressed NEFs raw files
-Z    "*.NEF"
# Exclude common movie file types from compression
-Z    "*.mp4"
-Z    "*.avi"
-Z    "*.mkv"
-Z    "*.mov"
-Z    "*.wmv"
-Z    "*.flv"
-Z    "*.mpeg"
-Z    "*.mpg"

# These are zip files. Not all are compressed, but considering that they can
# get quite large it is probably more prudent to leave this uncommented.
-Z    "*.pk3"
-Z    "*.zip"

-Z    "*.lz4"
-Z    "*.zoo"

-Z    "*.Po"
-Z    "*.aar"
-Z    "*.bx"
-Z    "*.chm"
-Z    "*.doc"
-Z    "*.epub"
-Z    "*.f3d"
-Z    "*.gpg"
-Z    "*.htmlz"
-Z    "*.iix"
-Z    "*.iso"
-Z    "*.jin"
-Z    "*.ods"
-Z    "*.odt"
-Z    "*.ser"
-Z    "*.svgz"
-Z    "*.swx"
-Z    "*.sxi"
-Z    "*.whl"
-Z    "*.wings"


# Dar archives (may be compressed).
-Z    "*.dar"

# Now we swap back to case sensitive mode for masks which is the default
#mode:
-acase

Backup definition example

This piece of configuration is a backup definition. It is placed in the BACKUP.D_DIR (see config file description). The name of the file is the name of the backup definition.

Backup definition naming rules:

Must contain only letters, numbers, spaces, or hyphens (-).
No underscores (_).
Must start and end with a letter or number (no leading/trailing spaces or hyphens). If you need to keep legacy names, run dar-backup with --allow-unsafe-definition-names to disable the check.

You can use as many backup definitions as you need.

Note 👉

Environment variables and tilde (~) not allowed here. dar does not expand them.

See TODO

 # Switch to ordered selection mode, which means that the following
 # options will be considered top to bottom
 -am

# Backup Root Dir
# This is the top directory, where the backups start.
#Directories mentioned below, are relative to the Root Dir.
 -R /home/user/

# Directories to backup below the Root dir
# uncomment the next line to backup only the Documents directory
# -g Documents

# Directories to exclude below the Root dir
 -P mnt
 -P tmp
 -P .cache
 -P .config/Code/CachedData
 
# compression level
 -z5

# no overwrite, if you rerun a backup, 'dar' halts and asks what to do
# due to the -Q option given to `dar`, the program will terminate and give en error.
 -n
 
# size of each slice in the archive
 --slice 7G

# bypass directores marked as cache directories
# http://dar.linux.free.fr/doc/Features.html
# https://bford.info/cachedir/
--cache-directory-tagging

Generate systemd files

The command dar-backup-systemd can generate and optionally install systemd units and timers.

The timers are set as the author uses them, modify to your taste and needs.

Example run:

dar-backup-systemd --venv /home/user/tmp/venv --dar-path /home/user/.local/dar/bin
Generated dar-full-backup.service and dar-full-backup.timer
  → Fires on: *-12-30 10:03:00
Generated dar-diff-backup.service and dar-diff-backup.timer
  → Fires on: *-*-01 19:03:00
Generated dar-incr-backup.service and dar-incr-backup.timer
  → Fires on: *-*-04/3 19:03:00
Generated dar-clean.service and dar-clean.timer
  → Fires on: *-*-* 21:07:00

Systemctl examples

I have dar-backup scheduled to run via systemd --user settings.

The files are located in: ~/.config/systemd/user

Once the .service and .timer files are in place, timers must be enabled and started.

systemctl --user enable dar-inc-backup.timer
systemctl --user start  dar-inc-backup.timer
systemctl --user daemon-reload

Verify your timers are set up as you want:

systemctl --user list-timers

Service: dar-backup --incremental-backup

This is an example of a systemd user service unit.

File: dar-incr-backup.service

/tmp/test$ dar-backup-systemd --venv '$HOME/programmer/dar-backup.py/venv'  --dar-path '$HOME/.local/dar/bin'

Generated dar-full-backup.service and dar-full-backup.timer
  → Fires on: *-12-30 10:03:00
Generated dar-diff-backup.service and dar-diff-backup.timer
  → Fires on: *-*-01 19:03:00
Generated dar-incr-backup.service and dar-incr-backup.timer
  → Fires on: *-*-04/3 19:03:00
Generated dar-cleanup.service and dar-cleanup.timer
  → Fires on: *-*-* 21:07:00
/tmp/test$ 
(venv) /tmp/test$ 
(venv) /tmp/test$ cat dar-incr-backup.service 
[Unit]
Description=dar-backup INCR
StartLimitIntervalSec=120
StartLimitBurst=1

[Service]
Type=oneshot
TimeoutSec=infinity
RemainAfterExit=no


ExecStart=/bin/bash -c 'PATH=$HOME/.local/dar/bin:$PATH && . $HOME/programmer/dar-backup.py/venv/bin/activate && dar-backup -I --verbose --log-stdout'

Timer: dar-backup --incremental-backup

This is an example of a systemd user timer

File: dar-incr-backup.timer

[Unit]
Description=dar-backup INCR timer

[Timer]
OnCalendar=*-*-04/3 19:03:00
Persistent=true

[Install]
WantedBy=timers.target

systemd timer note

📅 OnCalendar syntax is flexible — you can tweak backup schedules easily. Run systemd-analyze calendar to preview timers.

list contents of an archive

# Activate your virtual environment
source <the virtual evn>/bin/activate
dar-backup --list-contents media-files_INCR_2025-05-10
# Deactivate when done
deactivate

Note: --list-contents does not touch the restore directory. Cleanup only runs for operations that actually write to TEST_RESTORE_DIR (backup verification or a restore to the default location).

gives something like

[Saved][-]       [-L-][   0%][ ]  drwxrwxr-x   user user  2 Gio   Sat May 10 14:15:07 2025  home/user
[Saved][ ]       [-L-][  93%][ ]  -rw-rw-r--   user user  29 kio  Fri May  9 16:45:38 2025  home/user/data/2023/2023-02-11-Udstilling-Fredericia/DSC_0568.NEF.xmp
[Saved][-]       [-L-][   0%][ ]  drwxrwxr-x   user user  2 Gio   Fri May  9 12:49:04 2025  home/user/data/2025
[Saved][-]       [-L-][   1%][ ]  drwxrwxr-x   user user  193 Mio Thu May  8 15:59:17 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  15 Mio  Thu May  8 15:52:27 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0563.NEF
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  10 Mio  Thu May  8 15:52:27 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0563.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  9 Mio   Thu May  8 15:51:53 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0559.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  16 Mio  Thu May  8 15:51:45 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0558.NEF
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  12 Mio  Thu May  8 15:51:45 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0558.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  16 Mio  Thu May  8 15:51:24 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0557.NEF
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user  12 Mio  Thu May  8 15:51:23 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0557.JPG
[Saved][ ]       [-L-][  91%][ ]  -rw-rw-r--   user user  22 kio  Thu May  8 15:59:58 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0557.JPG.xmp
[Saved][ ]       [-L-][  92%][ ]  -rw-rw-r--   user user  30 kio  Thu May  8 16:00:36 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0557.NEF.xmp
[Saved][ ]       [-L-][  91%][ ]  -rw-rw-r--   user user  22 kio  Thu May  8 16:00:29 2025  home/user/data/2025/2025-05-09-Viltrox-25mm-AIR/DSC_0558.JPG.xmp

dar file selection examples

⚠️ Quoting matters

Always pass --selection as --selection="-I '*.NEF'" to ensure it’s treated as a single argument.

Avoid splitting --selection and the string into separate tokens.

Why does --selection give “expected one argument” error?

This happens when the shell splits the quoted string or interprets globs before dar-backup sees them.
✅ Use: --selection="-I '*.NEF'"
❌ Avoid: --selection "-I '*.NEF'"

💡 Tip: See dar's documentation

💡💡 Tip: To filter all the empty directories away that dar emits when listing contents, append this grep:

|grep -vE '\s+d[rwx-]{9}\s'

Example using the grep to discard directory noise from dar's output:

dar-backup --list-contents media-files_INCR_2025-05-10 --selection="-I '*Z50*' -X '*.xmp'" | grep -vE '\s+d[rwx-]{9}\s'
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 26  Mio Fri May  9 11:26:16 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0633.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 26  Mio Fri May  9 11:26:16 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0632.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 28  Mio Fri May  9 11:09:04 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0631.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 29  Mio Fri May  9 11:09:03 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0630.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 29  Mio Fri May  9 11:09:03 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0629.NEF
...

select a directory

Select files and sub directories in home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling

dar-backup --list-contents media-files_INCR_2025-05-10 --selection="-g 'home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling'"

gives

...
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 29  Mio Fri May  9 10:33:42 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0572.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 28  Mio Fri May  9 10:33:12 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0571.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 25  Mio Fri May  9 10:33:08 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0570.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 27  Mio Fri May  9 10:32:46 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0569.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 27  Mio Fri May  9 10:32:46 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0568.NEF
[Saved][-]       [-L-][   1%][ ]  drwxrwxr-x   user user 833 Mio Fri May  9 12:49:57 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/jpeg
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user 11  Mio Fri May  9 10:32:45 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/jpeg/Z50_0568.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user 11  Mio Fri May  9 10:32:46 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/jpeg/Z50_0569.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user 9   Mio Fri May  9 10:33:08 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/jpeg/Z50_0570.JPG
[Saved][ ]       [-L-][   1%][X]  -rw-rw-r--   user user 13  Mio Fri May  9 10:33:12 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/jpeg/Z50_0571.JPG
...

select files with "Z50" in the file name and exclude .xmp files

dar-backup --list-contents media-files_INCR_2025-05-10 --selection="-I '*Z50*' -X '*.xmp'"

gives something like

[Saved][-]       [-L-][   0%][ ]  drwxrwxr-x   user user 2   Gio Sat May 10 14:15:07 2025 home/user
[Saved][-]       [-L-][   0%][ ]  drwxrwxr-x   user user 2   Gio Fri May  9 12:49:04 2025 home/user/data/2025
[Saved][-]       [-L-][   1%][ ]  drwxrwxr-x   user user 193 Mio Thu May  8 15:59:17 2025 home/user/data/2025/2025-05-09-Viltrox-25mm-AIR
[Saved][-]       [-L-][   0%][ ]  drwxrwxr-x   user user 2   Gio Fri May  9 16:47:37 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 26  Mio Fri May  9 11:26:16 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0633.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 26  Mio Fri May  9 11:26:16 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0632.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 28  Mio Fri May  9 11:09:04 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0631.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 29  Mio Fri May  9 11:09:03 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0630.NEF
[Saved][ ]       [-L-][   0%][X]  -rw-rw-r--   user user 29  Mio Fri May  9 11:09:03 2025 home/user/data/2025/2025-05-09-Roskilde-Nordisk-udstilling/Z50_0629.NEF
...

Restoring

Point-in-Time Recovery (PITR)

Use the manager CLI to restore files as they existed at a specific time:

. <the virtual env>/bin/activate
manager --config-file <dar-backup.conf> \
  --backup-def <definition> \
  --restore-path tmp/path/to/file.txt \
  --when "2026-01-29 15:00:39" \
  --target /tmp/restore_pitr \
  --log-stdout --verbose
deactivate

Restore a directory (same idea, but the path is a directory):

. <the virtual env>/bin/activate
manager --config-file <dar-backup.conf> \
  --backup-def <definition> \
  --restore-path tmp/path/to/directory/ \
  --when "2026-01-29 15:00:39" \
  --target /tmp/restore_pitr \
  --log-stdout --verbose
deactivate

Dry-run the archive chain selection before restoring:

. <the virtual env>/bin/activate
manager --config-file <dar-backup.conf> \
  --backup-def <definition> \
  --restore-path tmp/path/to/directory \
  --when "2026-01-29 15:00:39" \
  --pitr-report \
  --log-stdout --verbose
deactivate

Notes:

--restore-path must be a relative path as stored in the catalog (no leading slash).
If a restore path is a directory and its name has no file extension, add a trailing / to make the intent explicit (e.g., photos/2026/01/). This avoids ambiguity with file paths that also lack extensions.
- Example (directory name has no extension):
  - manager --backup-def <definition> --restore-path "Automatic Upload/Per - iPhone/2026/01/" --when "now" --target /tmp/restore_pitr
--target is required to avoid accidental restores into the current working directory.
Protected targets are blocked (e.g., /etc, /usr, /bin, /var, /root, /boot, /lib, /proc, /sys, /dev).
--pitr-report does a dry-run chain selection; if it reports missing archives, a restore will fail until the catalog is rebuilt or missing archives are restored.
--pitr-report-first runs the same chain report before a restore and aborts if any archive is missing (useful as a safety preflight).
--when accepts natural-language date expressions via dateparser. Examples:
- "now"
- "2 weeks ago"
- "2025-10-05 14:30"
- yesterday 23:00
PITR restores use the catalog to select the correct archive chain (FULL → DIFF → INCR) and then restore directly with dar in that order.
- This avoids interactive dar_manager prompts (e.g., non‑monotonic mtimes often seen on pCloud/FUSE).
- Directories can get a new mtime when files inside them are added/removed; the chain restore ensures the correct tree is rebuilt even if mtimes look “too new”.
Missing archives:
- PITR uses the latest FULL, the latest DIFF after that FULL, and the latest INCR after that DIFF.
- If any archive slice in that chain is missing on disk, PITR restore fails and logs which archive slices are missing.
- A short Discord notice is sent (if configured) so missing archives are visible immediately.
Relocating archive paths in the catalog:
- The catalog stores absolute archive paths. If archives move (or a mountpoint changes), the catalog will still point to the old path.
- This can happen when manager DBs are moved to another disk and the archives are re-added from a different mountpoint.
- Use the built-in relocate command to rewrite a path prefix in-place:
  - Dry run:
    - manager --relocate-archive-path /old/path /new/path --relocate-archive-path-dry-run --backup-def <definition>
  - Apply:
    - manager --relocate-archive-path /old/path /new/path --backup-def <definition>
- Example (move /home/pj/mnt/dar to /mnt/dar):
  - manager --relocate-archive-path /home/pj/mnt/dar /mnt/dar --backup-def pCloudDrive
- Alternative quick fix: create a symlink from the old path to the new path.
Rebuilding a catalog after archive loss:
- If PITR fails due to missing archives, the catalog may no longer match what is actually on disk.
- You can rebuild the catalog from the remaining archives and then retry PITR (with the understanding that older restore points may no longer be possible).
- Example:
  - manager --create-db --config-file <dar-backup.conf>
  - manager --add-dir <backup_dir> --backup-def <definition> --config-file <dar-backup.conf>
- Or add individual archives:
  - manager --add-specific-archive <path/to/archive> --config-file <dar-backup.conf>

Example of the issue:

FULL backup at 10:00 with /data/photos/
You add files at 11:00 (directory mtime updates)
DIFF backup at 11:05
You request PITR restore of /data/photos/ at 10:30

dar_manager -w may say “directory did not exist before that time” because the directory mtime is now 11:00+.
The fallback still restores the correct tree as of 10:30 by applying the archive chain.

default location for restores

dar-backup will use the TEST_RESTORE_DIR location as the Root for restores, if the --restore-dir option has not been supplied.

See example below to see where files are restored to.

--restore-dir option

When the --restore-dir option is used for restoring, a directory must be supplied.

The directory supplied functions as the Root of the restore operation.

Example:

A backup has been taken using this backup definition:

-R /
-g home/user/Documents

When restoring and using /tmp for --restore-dir, the restored files can be found in /tmp/home/user/Documents

a single file

. <the virtual env>/bin/activate
dar-backup --restore <archive_name> --selection="-g path/to/file"
deactivate

a directory

. <the virtual env>/bin/activate
dar-backup --restore <archive_name> --selection="-g path/to/directory"
deactivate

.NEF from a specific date

The backed up directory contains *.NEF and *.xmp files.

Filtering:

Include files with "2024-06-16" in file name
Exclude files with file names ending in ".xmp"
Files must be in directory "home/user/tmp/LUT-play", compared to the file root (-Roption) in the backup.

. <the virtual env>/bin/activate
dar-backup --restore <archive_name>  --selection="-I '*2024-06-16*' -X '*.xmp' -g home/user/tmp/LUT-play"
deactivate

restore test fails with exit code 4

dar in newer versions emits a question about file ownership, which is "answered" with a "no" via the "-Q" option. That in turn leads to an error code 4.

Thus the dar option --comparison-field=ignore-owner has been placed in the supplied .darrc file (located in the virtual environment where dar-backup is installed).

This causes dar to restore without an error.

It is a good option when using dar as a non-privileged user.

restore test fails with exit code 5

If exit code 5 is emitted on the restore test, FSA (File System specific Attributes) could be the cause.

That (might) occur if you backup a file stored on one type of filesystem, and restore it on another type. My home directory is on a btrfs filesystem, while /tmp (for the restore test) is on zfs.

The restore test can result in an exit code 5, due to the different filesystems used. In order to avoid the errors, the option --fsa-scope none can be used. That will restult in FSA's not being restored.

If you need to use this option, un-comment it in the .darrc file (located in the virtual environment where dar-backup is installed)

Par2

Why keep PAR2 on a different storage device:

Reduces single-disk failure impact: bitrot on the archive disk does not affect the parity.
Easier offsite rotation: you can sync only the PAR2 sets to a different failure domain.

Redundancy guidance:

FULL backups: 10% is a practical default for larger data sets and longer retention.
DIFF/INCR: 5% is often enough because the delta is smaller and easier to re-create.
Increase the ratio if the storage is flaky or the backup is hard to re-run.

Rule of thumb table:

Backup type	Suggested PAR2 ratio	Notes
FULL	10%	Longer retention, larger data set
DIFF	5%	Smaller delta
INCR	5%	Smaller delta

For large, contiguous archives on reliable local storage, 7–8% has proven sufficient in practice; 10% remains a conservative default.

Cloud sync / air-gap note:

Syncing PAR2 sets to a different device or remote store protects against bitrot and small corruption, but it cannot recover a completely lost archive.
An air-gapped PAR2 store is useful when the archive disk is exposed to ransomware or accidental deletion.

Par2 to verify/repair

Par2 files kept with archives

If PAR2 files are stored next to the archives (legacy per-slice behavior), you can verify like this:

for file in <archive>*.dar.par2; do
  par2 verify "$file"
done

if there are problems with a slice, try to repair it like this:

  par2 repair <archive>.<slice number>.dar.par2

Par2 files in separate directory

See docs on disk layout matters

Test case proving this flow:

tests/test_par2_manifest.py

Par2 create redundancy files

If you have merged archives, you will need to create the .par2 redundency files manually. Here is an example

for file in <some-archive>_FULL_yyyy-mm-dd.*; do
  par2 c -r5 -n1 "$file"
done

where "c" is create, -r5 is 5% redundency and -n1 is 1 redundency file

If you want to create a single parity set for all slices in an archive:

par2 create -B <archive_dir> -r5 <par2_dir>/<archive_base>.par2 <archive_dir>/<archive_base>.*.dar

OBSERVE docs on disk layout matters

Points of interest

Limitations on File Names with Special Characters

dar-backup strictly validates all command-line arguments passed to its internal execution engine to protect against command injection and shell-based attacks. As part of this security measure, certain characters are disallowed in user-provided inputs — particularly those that carry special meaning in shell environments:

Disallowed characters include:

\$ & ; | > < ` \n

Why this matters

When restoring specific files using the --selection argument or similar mechanisms, filenames that contain one or more of these characters (e.g., file_with_currency$.txt) cannot be safely passed as command-line arguments. As a result, attempting to restore such a file by name using the CLI will result in a validation error.

✅ Backups and Restores Still Work

✅ These files are still backed up and restored automatically as part of normal FULL, DIFF, or INCR operations.

❌ They cannot be explicitly specified for restore using CLI options like --selection="-g path/to/file_with_currency$.txt".

Workarounds

If you need to restore such a file:

Perform a restore of the entire directory using a more general selection (e.g., --selection="-g path/to/parent-directory").

Manually retrieve the restored file afterward.

Restoring Files with Forbidden Characters in Their Names

The DAR Backup system enforces a strict command-line argument sanitizer to improve security and prevent shell injection attacks. As a result, certain characters are not allowed in filenames or arguments passed to the CLI, especially during restore operations. This includes characters like:

Character	Reason Blocked
`;`	Shell command separator
`&`	Background execution operator
`\|`	Pipe operator
`<` / `>`	Redirection operators
`#`	Shell comment
`	Command substitution
`"` / `'`	Quoting that may be unbalanced

However, backups of files with such names still work — they are preserved correctly within the archive. The limitation only applies to invoking restore commands via the CLI, where such filenames cannot be safely passed as arguments.

Backups: Safe and Fully Functional

Files with special characters in their names are backed up without issue. The only issue you might encounter is restoring a file and giving the file name on the command line (with forbidden characters.)

Restores via CLI: Limited by Sanitizer

Attempting to restore such files via:

    dar-backup restore --file "weird#name.txt"

...will fail with an error like:

    Unsafe argument detected: weird#name.txt

Workaround: Use `dar` Directly

You can always restore the file manually using the dar command-line utility itself, bypassing any CLI restrictions imposed by the backup tool.

Example: Manual Restore Using `dar`

    dar -x /path/to/backup/example -g "weird#name.txt"

Where:

/path/to/backup/example is the base name of the archive (without .dar, .1.dar, etc.).
"weird#name.txt" is the exact filename with the special character(s).

You may need to quote the argument or escape characters depending on your shell.

🧪 How to Locate Files with Forbidden Characters

To search for such files inside the archive:

    dar -l /path/to/backup/example | grep '[#;<>|&]'

This will help you identify files that require manual restoration.

Summary

🚫 Forbidden characters are blocked only in CLI arguments to maintain safety.
✅ Files containing these characters are still archived and restorable.
🛠 Use dar directly for full manual control when restoring such files.

Backup fails with error code 2

If you see something like this in the log file

2026-02-07 20:03:45,763 - INFO - ===> Starting INCR backup for /opt/dar-backup/backup.d/user-homedir
2026-02-07 20:03:45,878 - ERROR - Unexpected error during backup
2026-02-07 20:03:45,880 - ERROR - Error during INCR backup process for user-homedir: Unexpected error during backup: CommandResult:
  Return code: 2
  Note: <none>
  STDOUT: Error met while opening the last slice: Data corruption met at end of slice, unknown flag found. Trying to open the archive using the first slice.

it could be the DIFF file the INCR job is inspecting that has an error.

In this instance it was due to me doing a hard reboot during the DIFF backup due to a nfs issue, and did not clean up afterwards.

I looked at the trace log file to get more information and found this

2026-02-07 20:03:45,763 - DEBUG - Executing command: dar -c /mnt/dar/user-homedir_INCR_2026-02-07 -N -B /opt/dar-backup/venv/lib/python3.12/site-packages/dar_backup/.darrc -B /opt/dar-backup/backup.d/user-homedir -Q compress-exclusion verbose -A /mnt/dar/user-homedir_DIFF_2026-02-01 (timeout=86400s)
2026-02-07 20:03:45,764 - DEBUG - Process started pid=93372 cwd=/root
2026-02-07 20:03:45,840 - ERROR - FATAL error, aborting operation: Data corruption met at end of slice, unknown flag found

Running a test of the DIFF archive showed the error

dar -t /mnt/dar/user-homedir_DIFF_2026-02-01

which showed the archive is not healthy, so instead of making an INCR, I did a DIFF

dar-backup -D -d user-homedir --log-stdout

Now all is well again :-)

Merge FULL with DIFF, creating new FULL

Over time, the DIFF archives become larger and larger. At some point one wishes to create a new FULL archive to do DIFF's on. One way to do that, is to let dar create a FULL archive from scratch, another is to merge a FULL archive with a DIFF, and from there do DIFF's until they once again gets too large for your taste.

I do backups of my homedir. Here it is shown how a FULL archive is merged with a DIFF, creating a new FULL archive.

dar --merge user-homedir_FULL_2021-09-12  -A user-homedir_FULL_2021-06-06  -@user-homedir_DIFF_2021-08-29 -s 12G

# test the new FULL archive
dar -t user-homedir_FULL_2021-09-12

# create Par2 redundancy files
for file in user-homedir_FULL_yyyy-mm-dd.*.dar; do
  par2 c -r5 -n1 "$file"
done

dar manager databases

dar-backup now saves archive catalogs in dar catalog databases.

This makes it easier to restore to a given date when having many FULL, DIFF and INCR archives.

If the manager does not add an archive to it's catalog database, dar-backup will log an error and continue. The important part is verify the archive is usable and continue to other backup definitions.

Performance tip due to par2

This dar benchmark page has an interesting note on the slice size.

Slice size should be smaller than available RAM, apparently a large performance hit can be avoided keeping the par2 data in memory.

.darrc sets -vd -vf (since v0.6.4)

These .darrc settings make dar print the current directory being processed (-vd) and some stats after (-vf)

This is very useful in very long running jobs to get an indication that the backup is proceeding normally.

The dar output is streamed to the dar-backup-commands.log file.

Separate log file for command output

Dar-backup's log file is called dar-backup.log.

In order to not clutter that log file with the output of commands being run, a new secondary log file has been introduced dar-backup-commands.log.

The secondary log file can get quite cluttered, if you want to remove the clutter, run the clean-logscript with the --file option, or simply delete it.

Trace Logging (Debug details)

To keep the main log file clean while preserving essential debugging information, dar-backup creates a separate trace log file (e.g., dar-backup.trace.log) alongside the main log.

Main Log (dar-backup.log): Contains clean, human-readable INFO/ERROR messages. Stack traces are suppressed here.
Trace Log (dar-backup.trace.log): Captures ALL messages at DEBUG level, including full exception stack traces. Use this file for debugging crashes or unexpected behavior.

You can configure the rotation of this file in [MISC]:

[MISC]
# ... other settings ...
TRACE_LOG_MAX_BYTES = 10485760  # 10 MB default
TRACE_LOG_BACKUP_COUNT = 1      # Keep 1 old trace file (default)

Skipping cache directories

The author uses the --cache-directory-tagging option in his backup definitions.

The effect is that directories with the CACHEDIR.TAG file are not backed up. Those directories contain content fetched from the net, which is of an ephemeral nature and probably not what you want to back up.

If the option is not in the backup definition, the cache directories are backed up as any other.

Shell autocompletion

The dar-backup, manager, and cleanup scripts now support dynamic Bash tab-completion, making them easier and faster to use.

✅ Features

Autocomplete for all long options (--config-file, --restore, etc.)
Dynamic suggestions based on your config:
--backup-definition shows available definitions from backup.d/
show relevant archives when a backup definition has been chosen:

dar-backup: --restore, --list-contents, and --alternate-reference-archive

cleanup: --cleanup-specific-archives

manager: --list-archive-contents, --add-specific-archive (autocomplete those *not in the catalog database), --remove-specific-archive
Supports paths like ~ and $HOME correctly

Use it

Try typing:

dar-backup --<TAB>

You should see all available flags like --full-backup, --restore, etc.

Try completion of backup definition and then list contents:

    dar-backup --backup-definition <TAB>
    dar-backup -d <the chosen backup-definition> --list-contents <TAB>

Archive name completion (smart, context-aware)

When using manager--list-archive-contents, the tab-completer suggests valid archive names.

The behavior is smart and context-aware:

If a --backup-definition (-d) is provided, archive suggestions are restricted to that .db catalog.
If no backup definition is given, the completer will:
- Scan all .db files in the backup_dir
- Aggregate archive names across all catalogs
- Sort results by:
  - Backup name (e.g. pCloudDrive, media-files)
  - Date inside the archive name (e.g. 2025-04-19)

It’s blazing fast and designed for large backup sets.

# With a backup definition
manager -d pCloudDrive --list-archive-contents <TAB>
# ⤷ Suggests: pCloudDrive_FULL_2025-03-04, pCloudDrive_INCR_2025-04-19, ...

# Without a backup definition
manager --list-archive-contents <TAB>
# ⤷ Suggests: all archives across all known backup definitions
# ⤷ Example: media-files_FULL_2025-01-04, pCloudDrive_INCR_2025-04-19, ...

# Filter by prefix
manager --list-archive-contents media-<TAB>
# ⤷ Suggests: media-files_FULL_2025-01-04, media-files_INCR_2025-02-20, ...

Enabling Bash completion

Try auto completion in your session:

eval "$(register-python-argcomplete dar-backup)"
eval "$(register-python-argcomplete cleanup)"
eval "$(register-python-argcomplete manager)"
#complete -o nosort -C 'python -m argcomplete cleanup' cleanup
#complete -o nosort -C 'python -m argcomplete manager' manager

To make it persistent across sessions, add this to your ~/.bashrc:

# Enable autocompletion for dar-backup
eval "$(register-python-argcomplete dar-backup)"
eval "$(register-python-argcomplete cleanup)"
eval "$(register-python-argcomplete manager)"
# This disables bash sorting, so sorting is by <backup definition> and <date>
#complete -o nosort -C 'python -m argcomplete cleanup' cleanup
#complete -o nosort -C 'python -m argcomplete manager' manager

If you're using a virtual environment and register-python-argcomplete isn't in your global PATH, use:

# Enable autocompletion for dar-backup
eval "$($(which register-python-argcomplete) dar-backup)"
eval "$($(which register-python-argcomplete) cleanup)"
eval "$($(which register-python-argcomplete) manager)"

# If it's not working, try reactivating your virtualenv and restarting your terminal.

Then reload your shell:

source ~/.bashrc

Enable Zsh Completion

If you're using Zsh, add this to your .zshrc:

autoload -U bashcompinit
bashcompinit
eval "$(register-python-argcomplete dar-backup)"
eval "$(register-python-argcomplete cleanup)"
eval "$(register-python-argcomplete manager)"

Then reload Zsh:

source ~/.zshrc

Easy development setup

It is very easy to have your own development environment.

git clone https://github.com/per2jensen/dar-backup.git
cd dar-backup/v2
./build.py

This script:

Creates a Python virtual environment called venv
pip install hatch

pip install the development environment as setup in pyproject.toml

--

dev = [
"pytest",
"wheel>=0.45.1",
"requests>=2.32.2",
"coverage>=7.8.2",
"pytest>=8.4.0",
"pytest-cov>=6.1.1",
"psutil>=7.0.0",
"pytest-timeout>=2.4.0",
"httpcore>=0.17.3",
"h11>=0.16.0",
"zipp>=3.19.1",
"anyio>=4.4.0",
"black>=25.1.0"]

✅ Your environment is now ready to activate and test!

Activate and run the test suite:

source venv/bin/activate # activate the virtual env
pytest                   # run the test suite

Todo

v2-1.2

Generate a working config from provided paths to archives and catalogs
- Useful for future restores, possibly in many years.
Support dar version 2.8.x

v2-1.3

Use dar's PKI encryption features
- Figure out how it works, the use cases, possible limitations to current work flows

Other stuff

Perhaps look into pre-processing backup definitions. As dar does not expand env vars dar-backup could do so and feed the result to dar.
Add option to dar-backup to use the dar option --fsa-scope none

Known Limitations / Edge Cases

Does not currently encrypt data (by design — relies on encrypted storage)
- PKI contemplated for v2-1.3.0
One backup definition per file in backups.d/
- this assumption is built deep into dar-backup

Projects these scripts benefit from

Reference

CLI Tools Overview

Command	Description
dar-backup	Perform full, differential, or incremental backups with verification and restore testing
manager	Maintain and query catalog databases for archives
cleanup	Remove outdated DIFF/INCR archives (and optionally FULLs)
clean-log	Clean up excessive log output from dar command logs
dar-backup-systemd	Generate (and optionally install) systemd timers and services for automated backups
installer	Set up directories and optionally create catalog databases according to a config file
demo	Set up required directories and config files for a demo

Test coverage

Test selection with markers

The test suite is annotated with these markers:

unit (fast, pure logic)
component (subprocess boundary with mocks/lightweight commands)
integration (end-to-end workflows; external tools)
slow (long-running/heavier integration)
live_discord (sends real webhook messages; opt-in only)

Common runs

# Fast local loop (unit + component)
pytest -m "unit or component"

# Integration (exclude slow + live webhook)
pytest -m "integration and not slow and not live_discord"

# Slow-only
pytest -m slow

# Full suite (default pytest.ini already excludes live_discord)
pytest -m "not live_discord"

# Live webhook (requires DAR_BACKUP_DISCORD_WEBHOOK_URL)
pytest -m live_discord

Run all tests

pytest

Results for version 1.1.0 (pre-release, Feb 1, 2026) in this report:

===================================== test session starts =====================================
platform linux -- Python 3.12.3, pytest-8.4.0, pluggy-1.6.0
rootdir: /home/pj/git/dar-backup/v2
configfile: pytest.ini
testpaths: tests
plugins: anyio-4.9.0, timeout-2.4.0, cov-6.1.1, mock-3.15.1
timeout: 1800.0s
timeout method: signal
timeout func_only: False
collected 559 items / 1 deselected / 558 selected                                             

tests/test_add_old_archive_confirmation.py ....                                         [  0%]
tests/test_alternate_reference_archive.py ...                                           [  1%]
tests/test_autocompletion_install.py ...                                                [  1%]
tests/test_binary_info.py ......                                                        [  2%]
tests/test_bitrot.py ..                                                                 [  3%]
tests/test_clean_log.py ....................                                            [  6%]
tests/test_cleanup.py ...............................                                   [ 12%]
tests/test_command_runner.py .........................................                  [ 19%]
tests/test_config_comments.py .                                                         [ 19%]
tests/test_config_settings.py ..............                                            [ 22%]
tests/test_create_backup_command.py ...                                                 [ 22%]
tests/test_create_full_diff_incr_backup.py ..........                                   [ 24%]
tests/test_dar_backup.py .......................................................        [ 34%]
tests/test_dar_backup_additional_coverage.py .......................                    [ 38%]
tests/test_dar_backup_startup.py ..                                                     [ 39%]
tests/test_darrc.py ..                                                                  [ 39%]
tests/test_demo.py .............                                                        [ 41%]
tests/test_discord_webhook.py ..                                                        [ 42%]
tests/test_filter_darrc_file.py .                                                       [ 42%]
tests/test_generic_backup_command_execution.py .                                        [ 42%]
tests/test_get_config_file.py .......                                                   [ 43%]
tests/test_gpt_file_compression.py .                                                    [ 43%]
tests/test_gpt_tests.py .......                                                         [ 45%]
tests/test_installer.py ..................                                              [ 48%]
tests/test_links.py .                                                                   [ 48%]
tests/test_list_definitions.py .                                                        [ 48%]
tests/test_listing.py ...                                                               [ 49%]
tests/test_logging_trace.py ..                                                          [ 49%]
tests/test_manager.py ................................................................. [ 61%]
                                                                                        [ 61%]
tests/test_manager_coverage.py ..................................                       [ 67%]
tests/test_par2.py .                                                                    [ 67%]
tests/test_par2_manifest.py .                                                           [ 67%]
tests/test_par2_multi_definitions.py .                                                  [ 67%]
tests/test_par2_overrides.py .                                                          [ 68%]
tests/test_pitr.py ..............................................                       [ 76%]
tests/test_pitr_integration.py .....                                                    [ 77%]
tests/test_postreq.py .                                                                 [ 77%]
tests/test_preflight.py ...                                                             [ 77%]
tests/test_prereq.py .                                                                  [ 78%]
tests/test_readme_changelog.py ..........                                               [ 79%]
tests/test_restore.py ....                                                              [ 80%]
tests/test_run_command.py ......s                                                       [ 81%]
tests/test_sanity_checks.py .................                                           [ 84%]
tests/test_space_definition.py .                                                        [ 85%]
tests/test_startup_cleanup.py .......                                                   [ 86%]
tests/test_status_indicators.py .......                                                 [ 87%]
tests/test_stress.py .                                                                  [ 87%]
tests/test_systemd_unit_generation.py ..........                                        [ 89%]
tests/test_trace_logging.py ..                                                          [ 89%]
tests/test_util.py ..........................................                           [ 97%]
tests/test_util_completers.py ..........                                                [ 99%]
tests/test_verbose.py ...                                                               [ 99%]
tests/test_verify_cleanup.py .                                                          [100%]

======================================= tests coverage ========================================
_______________________ coverage: platform linux, python 3.12.3-final-0 _______________________

Name                                   Stmts   Miss Branch BrPart  Cover
------------------------------------------------------------------------
src/dar_backup/__about__.py                3      0      0      0   100%
src/dar_backup/__init__.py                 0      0      0      0   100%
src/dar_backup/clean_log.py              114     10     46      2    91%
src/dar_backup/cleanup.py                294     42    100      9    87%
src/dar_backup/command_runner.py         231     20     82     10    90%
src/dar_backup/config_settings.py        162      9     62     10    92%
src/dar_backup/dar_backup.py            1027     55    420     49    92%
src/dar_backup/dar_backup_systemd.py      56      1     10      1    97%
src/dar_backup/demo.py                   100      1     34      2    98%
src/dar_backup/exceptions.py               2      0      0      0   100%
src/dar_backup/installer.py              120      4     54      4    95%
src/dar_backup/manager.py               1105     91    454     38    91%
src/dar_backup/rich_progress.py           70      2     30      3    95%
src/dar_backup/util.py                   521     43    142     24    90%
------------------------------------------------------------------------
TOTAL                                   3805    278   1434    152    91%
Coverage XML written to file /tmp/coverage.xml
================== 557 passed, 1 skipped, 1 deselected in 409.66s (0:06:49) ===================

Dar-backup options

This script does backups including par2 redundancy, validation and restoring.

Available options:

-F, --full-backup                    Perform a full backup.
-D, --differential-backup            Perform a differential backup.
-I, --incremental-backup             Perform an incremental backup.
-d, --backup-definition <name>       Specify the backup definition file.
--alternate-reference-archive <file> Use a different archive for DIFF/INCR backups.
-c, --config-file <path>             Specify the path to the configuration file.
--darrc <path>                       Specify an optional path to .darrc.
--examples                           Show examples of using dar-backup.py.
-l, --list                           List available backups.
--list-contents <archive>            List the contents of a specified archive.
--list-definitions                   List backup definitions from BACKUP.D_DIR.
--selection <params>                 Define file selection for listing/restoring.
--restore <archive>                  Restore a specified archive.
-r, --restore <archive>              Restore archive.
--restore-dir                        Directory on which to restore
--verbose                            Enable verbose output.
--suppress-dar-msg                   Filter out this from the darrc: "-vt", "-vs", "-vd", "-vf", "-va"
--log-level <level>                  `debug` or `trace`, default is `info`.
--log-stdout                         Also print log messages to stdout.
--do-not-compare                     Do not compare restores to file system.
--allow-unsafe-definition-names      Disable backup definition name validation (allows underscores or other characters).
--preflight-check                    Run preflight checks and exit (runs automatically; this flag just exits after checks).
--examples                           Show examples of using dar-backup.
--readme                             Print README.md and exit
--readme-pretty                      Print README.md with Markdown styling and exit
--changelog                          Print Changelog and exit
--changelog-pretty                   Print Changelog with Markdown styling and exit
-v, --version                         Show version and license information.

Dar-backup exit codes

0: Success.
1: Error (backup/restore/preflight failure).
2: Warning (restore test failed or backup already exists and is skipped).
127: Typically an error during startup, file or config value missing
- if the dar -t test fails, exit code 1 is emitted
- restore tests could fail if the source file has changed after the backup

Dar-backup env vars

Env var	Value	Description
DAR_BACKUP_CONFIG_FILE	Full path to config file	Overrides built-in default, overridden by --config-file
DAR_BACKUP_DISCORD_WEBHOOK_URL	https://discord.com/api/webhooks/\<userID>/<webhook UUID>	The full url
DAR_BACKUP_COMMAND_TIMEOUT_SECS	-1 or > 0	Overrides config `COMMAND_TIMEOUT_SECS`. Use `-1` to disable timeouts.

Manager Options

This script manages dar databases and catalogs.

Available options:

-c, --config-file <path>             Path to dar-backup.conf.
--create-db                          Create missing databases for all backup definitions.
--alternate-archive-dir <path>       Use this directory instead of BACKUP_DIR in the config file.
--add-dir <path>                     Add all archive catalogs in this directory to databases.
-d, --backup-def <name>              Restrict operations to this backup definition.
--add-specific-archive <archive>     Add a specific archive to the catalog database.
--remove-specific-archive <archive>  Remove a specific archive from the catalog database.
-l, --list-catalogs                  List catalogs in databases for all backup definitions.
--list-archive-contents <archive>    List the contents of an archive’s catalog by archive name.
--find-file <file>                   Search catalogs for a specific file.
--restore-path <path> [<path> ...]   Restore specific path(s) (Point-in-Time Recovery).
--when <timestamp>                   Date/time for restoration (used with --restore-path).
--target <path>                      Target directory for restoration (default: current dir).
--pitr-report                        Report PITR archive chain for --restore-path/--when without restoring.
--pitr-report-first                  Run PITR chain report before restore and abort if missing archives.
--relocate-archive-path <old> <new>  Rewrite archive path prefix in the catalog DB (requires --backup-def).
--relocate-archive-path-dry-run      Show archive path changes without applying them (use with --relocate-archive-path).
--verbose                            Enable verbose output.
--log-level <level>                  Set log level (`debug` or `trace`, default is `info`).

#### Manager env vars

| Env var | Value | Description |
| --- | --- | --- |
| DAR_BACKUP_CONFIG_FILE | path to the config file | Default is $HOME/.config/dar-backup/dar-backup.conf |
| DAR_BACKUP_COMMAND_TIMEOUT_SECS | -1 or > 0 | Overrides config `COMMAND_TIMEOUT_SECS`. Use `-1` to disable timeouts. |

### Cleanup options

This script removes old backups and par2 files according to `[AGE]` settings in config file.

Catalogs in catalog databases are also removed.

Supported options:

```bash
-d, --backup-definition                           Backup definition to cleanup.
-c, --config-file                                 Path to 'dar-backup.conf'
-v, --version                                     Show version & license information.
--alternate-archive-dir                           Clean up in this directory instead of the default one.
--cleanup-specific-archives "<archive>, <>, ..."  Comma separated list of archives to cleanup.
-l, --list                                       List available archives (filter using the -d option).
--dry-run                                        Show what would be deleted without removing files.
--verbose                                         Print various status messages to screen.
--log-level <level>                               `debug` or `trace`, default is `info`", default="info".
--log-stdout                                      Print log messages to stdout.
--test-mode                                       This is used when running pytest test cases

Cleanup env vars

Env var	Value	Description
DAR_BACKUP_CONFIG_FILE	path to the config file	Default is $HOME/.config/dar-backup/dar-backup.conf
DAR_BACKUP_COMMAND_TIMEOUT_SECS	-1 or > 0	Overrides config `COMMAND_TIMEOUT_SECS`. Use `-1` to disable timeouts.

Clean-log options

This script removes excessive logging output from dar logs, improving readability and efficiency. Available options:

-f, --file <path>          Specify the log file(s) to be cleaned.
-c, --config-file <path>   Path to dar-backup.conf.
--dry-run                  Show which lines would be removed without modifying the file.
-v, --version              Display version and licensing information.
-h, --help                 Displays usage info

Dar-backup-systemd options

Generates and optionally install systemd user service units and timers.

-h, --help           Show this help message and exit
--venv VENV          Path to the Python venv with dar-backup
--dar-path DAR_PATH  Optional path to dar binary's directory
--install            Install the units to ~/.config/systemd/user

Installer options

Sets up dar-backup according to provided config file.

The installer creates the necessary backup catalog databases if --create-db is given.

--config                 Path to a config file. The configured directories will be created.
--create-db              Create backup catalog databases. Use this option with `--config`.
--install-autocompletion Add bash or zsh auto completion - idempotent.
--remove-autocompletion  Remove the auto completion from bash or zsh.
-v, --version            Display version and licensing information.
-h, --help               Displays usage info.

Demo options

Sets up dar-backup in a demo configuration.

It is non-destructive and stops if directories are already in place.

Create directories:

~/.config/dar-backup/
- ~/.config/dar-backup/backup.d/
~/dar-backup/
- ~/dar-backup/backups/
- ~/dar-backup/restore/

Sets up demo config files:

~/.config/dar-backup/dar-backup.conf
~/.config/dar-backup/backup.d/demo

-i, --install       Sets up `dar-backup`.
--root-dir          Specify the root directory for the backup.
--dir-to-backup     Directory to backup, relative to the root directory.
--backup-dir        Directory where backups and redundancy files are put.
--override          By default, the script will not overwrite existing files or directories.
                    Use this option to override this behavior.
--generate          Generate config files and put them in /tmp/ for inspection
                    without writing to $HOME.
-v, --version       Display version and licensing information.
-h, --help          Displays usage info

Config changes

1.0.1

DISCORD WEBHOOK

For Discord notifications use the DAR_BACKUP_DISCORD_WEBHOOK_URL environment variable. It should not be placed in the config file.

DAR_BACKUP_DISCORD_WEBHOOK_URL is the entire endpoint like this:

export DAR_BACKUP_DISCORD_WEBHOOK_URL=https://discord.com/api/webhooks/\<userId\>/\<uuid\>

Restore test config

Restore tests choose random files from the archive and compare them with the live filesystem. To avoid noisy paths (caches, temp files, logs), you can exclude candidates before the random selection happens. All matching is case-insensitive.

Config keys (in [MISC]):

RESTORETEST_EXCLUDE_PREFIXES: comma-separated path prefixes to skip. Matches from the start of the path (after trimming a leading "/"). Use trailing "/" for directories.
RESTORETEST_EXCLUDE_SUFFIXES: comma-separated filename suffixes to skip.
RESTORETEST_EXCLUDE_REGEX: optional regex to skip anything matching the path.

Example:

[MISC]
RESTORETEST_EXCLUDE_PREFIXES = .cache/, .local/share/Trash/, .mozilla/, snap/firefox/common/.mozilla/
RESTORETEST_EXCLUDE_SUFFIXES = .sqlite-wal, .sqlite-shm, .log, .tmp, .lock, .journal
RESTORETEST_EXCLUDE_REGEX = (^|/)(Cache|cache|Logs|log)/

Regex tips (case-insensitive):

Match common cache/log directories anywhere: (^|/)(cache|logs)/
Skip thumbnails and temp dirs: (^|/)(thumbnails|tmp|temp)/
Exclude browser profile noise while keeping other files: (^|/)\.mozilla/|/snap/firefox/common/\.mozilla/

Par2

New optional PAR2 settings were added to the config file. If none of these keys are added, dar-backup behaves exactly as before (PAR2 files next to archives, per-slice parity).

Name	Description	When it is in effect	Suggested value
PAR2_DIR	Directory to store .par2 and .vol*.par2 files	When set	A different device or mount from BACKUP_DIR
PAR2_RATIO_FULL	Redundancy percent for FULL	When set	10 (%)
PAR2_RATIO_DIFF	Redundancy percent for DIFF	When set	5 (%)
PAR2_RATIO_INCR	Redundancy percent for INCR	When set	5 (%)
PAR2_RUN_VERIFY	Verify after create	When set	false

Notes:

PAR2_RATIO_*, and PAR2_RUN_VERIFY apply even if PAR2_DIR is not set (i.e. par2 output stays next to the archives).

Per-backup overrides use a section named after the backup definition with the same PAR2_* keys:


######################################################################
# Per-backup configuration example overrides
######################################################################

# --------------------------------------------------------------------
# Per-backup overrides (section name must match backup.d filename stem)
# Example: backup.d/home.conf  ->  [home]
# --------------------------------------------------------------------

#[home]
# Disable PAR2 entirely for this backup definition
PAR2_ENABLED = false
#
#[media]
# Store PAR2 files in a separate location for this backup definition
#PAR2_DIR = /samba/par2/media
# Raise redundancy only for FULL
#
[documents]
# Run verify par2 sets after creation
PAR2_RUN_VERIFY = true
#
#[etc]
# Keep global PAR2 settings but tweak ratios for this backup definition
# RATIO is given in percent (%)
#PAR2_RATIO_FULL = 15  
#PAR2_RATIO_DIFF = 8
#PAR2_RATIO_INCR = 8

Per-backup override test case: tests/test_par2_overrides.py

1.0.2

Trace Logging

To support debugging without cluttering the main log file, a secondary trace log is now created (e.g., dar-backup.trace.log). This file captures all DEBUG level messages and full exception stack traces.

You can configure its rotation in the [MISC] section:

TRACE_LOG_MAX_BYTES: Max size of the trace log file in bytes. Default is 10485760 (10 MB).
TRACE_LOG_BACKUP_COUNT: Number of rotated trace log files to keep. Default is 1.

Example:

[MISC]
TRACE_LOG_MAX_BYTES = 10485760
TRACE_LOG_BACKUP_COUNT = 1

Command output Capture

New optional [MISC] setting: COMMAND_CAPTURE_MAX_BYTES (default 102400).
- Limits how much stdout/stderr is kept in memory per command while still logging full output.
- Set to 0 to disable buffering entirely. Command output is still streamed to dar-backup-commands.log
- If set to 0, the calling function cannot rely on output from the executed command. The exit value is the only result provided.

Example:

[MISC]
COMMAND_CAPTURE_MAX_BYTES = 102400

1.1.0

COMMAND_TIMEOUT_SECS=-1 now disables timeout for commands executed.

1.1.1

Env var DAR_BACKUP_COMMAND_TIMEOUT_SECS now overrides config file var COMMAND_TIMEOUT_SECS.

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License

per2jensen/dar-backup

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dar-backup

TL;DR

Table of Contents

My use case

My setup

Why PAR2 is especially good for portable / offsite copies

Design choices

Features

License

Quick Guide

Status

GPG Signing key

Homepage - Github

Community

Requirements

dar-backup principles

dar-backup overview

dar-backup

cleanup

manager

How to run

1 - installation

2 - configuration

3 - generate catalog databases

4 - give dar-backup a spin

5 - deactivate venv

Config

Config file

.darrc

Backup definition example

Generate systemd files

Systemctl examples

Service: dar-backup --incremental-backup

Timer: dar-backup --incremental-backup

systemd timer note

list contents of an archive

dar file selection examples

select a directory

select files with "Z50" in the file name and exclude .xmp files

Restoring

Point-in-Time Recovery (PITR)

default location for restores

--restore-dir option

a single file

a directory

.NEF from a specific date

restore test fails with exit code 4

restore test fails with exit code 5

Par2

Par2 to verify/repair

Par2 files kept with archives

Par2 files in separate directory

Par2 create redundancy files

Points of interest

Limitations on File Names with Special Characters

Why this matters

Workarounds

Restoring Files with Forbidden Characters in Their Names

Backups: Safe and Fully Functional

Restores via CLI: Limited by Sanitizer

Workaround: Use dar Directly

Example: Manual Restore Using dar

🧪 How to Locate Files with Forbidden Characters

Summary

Backup fails with error code 2

Merge FULL with DIFF, creating new FULL

dar manager databases

Performance tip due to par2

.darrc sets -vd -vf (since v0.6.4)

Separate log file for command output

Trace Logging (Debug details)

Skipping cache directories

Shell autocompletion

Use it

`dar-backup`

Workaround: Use `dar` Directly

Example: Manual Restore Using `dar`

Packages