Rdup is a utility inspired by rsync and the plan9 way of doing backups. Rdup itself does not backup anything, it only print a list of absolute file names to standard output. Auxiliary scripts are needed that act on this list and implement the backup strategy.

Duplicity backs up directories by producing encrypted tar-format volumes and uploading them to a remote or local file server. Because duplicity uses librsync, the incremental archives are space efficient and only record the parts of files that have changed since the last backup. Because duplicity uses GnuPG to encrypt and/or sign these archives, they will be safe from spying and/or modification by the server.

Libarchive provides a flexible interface for reading and writing archives in various formats such as tar and cpio. Libarchive also supports reading and writing archives compressed using various compression filters such as gzip and bzip2. The library is inherently stream-oriented; readers serially iterate through the archive, writers serially add things to the archive. In particular, note that there is currently no built-in support for random access nor for in-place modification. This package provides the bsdcat, bsdcpio and bsdtar commands.

rsnapshot is a file system snapshot utility based on rsync. rsnapshot makes it easy to make periodic snapshots of local machines, and remote machines over SSH. To reduce the disk space required for each backup, rsnapshot uses hard links to deduplicate identical files.

Btar is a tar-compatible archiver which allows arbitrary compression and ciphering, redundancy, differential backup, indexed extraction, multicore compression, input and output serialisation, and tolerance to partial archive errors.

SnapRAID backs up files stored across multiple storage devices, such as disk arrays, in an efficient way reminiscent of its namesake RAID level 4.

Instead of creating a complete copy of the data like classic backups do, it saves space by calculating one or more sets of parity information that's a fraction of the size. Each parity set is stored on an additional device the size of the largest single storage volume, and protects against the loss of any one device, up to a total of six. If more devices fail than there are parity sets, (only) the files they contained are lost, not the entire array. Data corruption by unreliable devices can also be detected and repaired.

SnapRAID is distinct from actual RAID in that it operates on files and creates distinct snapshots only when run. It mainly targets large collections of big files that rarely change, like home media centers. One disadvantage is that all data not in the latest snapshot may be lost if one device fails. An advantage is that accidentally deleted files can be recovered, which is not the case with RAID.

It's also more flexible than true RAID: devices can have different sizes and more can be added without disturbing others. Devices that are not in use can remain fully idle, saving power and producing less noise.

Restic is a program that does backups right and was designed with the following principles in mind:

• Easy: Doing backups should be a frictionless process, otherwise you might be tempted to skip it. Restic should be easy to configure and use, so that, in the event of a data loss, you can just restore it. Likewise, restoring data should not be complicated.

• Fast: Backing up your data with restic should only be limited by your network or hard disk bandwidth so that you can backup your files every day. Nobody does backups if it takes too much time. Restoring backups should only transfer data that is needed for the files that are to be restored, so that this process is also fast.

• Verifiable: Much more important than backup is restore, so restic enables you to easily verify that all data can be restored.

• Secure: Restic uses cryptography to guarantee confidentiality and integrity of your data. The location the backup data is stored is assumed not to be a trusted environment (e.g. a shared space where others like system administrators are able to access your backups). Restic is built to secure your data against such attackers.

• Efficient: With the growth of data, additional snapshots should only take the storage of the actual increment. Even more, duplicate data should be de-duplicated before it is actually written to the storage back end to save precious backup space.

Dump examines files in a file system, determines which ones need to be backed up, and copies those files to a specified disk, tape or other storage medium. Subsequent incremental backups can then be layered on top of the full backup. The restore command performs the inverse function of dump; it can restore a full backup of a file system. Single files and directory subtrees may also be restored from full or partial backups in interactive mode.

Libarchive provides a flexible interface for reading and writing archives in various formats such as tar and cpio. Libarchive also supports reading and writing archives compressed using various compression filters such as gzip and bzip2. The library is inherently stream-oriented; readers serially iterate through the archive, writers serially add things to the archive. In particular, note that there is currently no built-in support for random access nor for in-place modification. This package provides the bsdcat, bsdcpio and bsdtar commands.

Rdiff-backup backs up one directory to another, possibly over a network. The target directory ends up a copy of the source directory, but extra reverse diffs are stored in a special subdirectory of that target directory, so you can still recover files lost some time ago. The idea is to combine the best features of a mirror and an incremental backup. Rdiff-backup also preserves subdirectories, hard links, dev files, permissions, uid/gid ownership, modification times, extended attributes, acls, and resource forks. Also, rdiff-backup can operate in a bandwidth efficient manner over a pipe, like rsync. Thus you can use rdiff-backup and ssh to securely back a hard drive up to a remote location, and only the differences will be transmitted. Finally, rdiff-backup is easy to use and settings have sensible defaults.

Borg is a deduplicating backup program. Optionally, it supports compression and authenticated encryption. The main goal of Borg is to provide an efficient and secure way to backup data. The data deduplication technique used makes Borg suitable for daily backups since only changes are stored. The authenticated encryption technique makes it suitable for storing backups on untrusted computers.

Btrbk is a backup tool for Btrfs subvolumes, taking advantage of Btrfs specific capabilities to create atomic snapshots and transfer them incrementally to your backup locations. The source and target locations are specified in a config file, which allows easily configuring simple scenarios like e.g. a laptop with locally attached backup disks, as well as more complex ones, e.g. a server receiving backups from several hosts via SSH, with different retention policy. It has features such as:

• atomic snapshots

• incremental backups

• flexible retention policy

• backups to multiple destinations

• transfer via SSH

• resume backups (for removable and mobile devices)

• archive to offline storage

• encrypted backups to non-btrfs storage

• wildcard subvolumes (useful for Docker and LXC containers)

• transaction log

• comprehensive list and statistics output

• resolve and trace Btrfs parent-child and received-from relationships

• list file changes between backups

• calculate accurate disk space usage based on block regions.

Btrbk is designed to run as a cron job for triggering periodic snapshots and backups, as well as from the command line (e.g. for instantly creating additional snapshots).

GNU Binutils is a collection of tools for working with binary files. Perhaps the most notable are "ld", a linker, and "as", an assembler. Other tools include programs to display binary profiling information, list the strings in a binary file, and utilities for working with archives. The "bfd" library for working with executable and object formats is also included.

The Time Zone Database (often called tz or zoneinfo) contains code and data that represent the history of local time for many representative locations around the globe. It is updated periodically to reflect changes made by political bodies to time zone boundaries, UTC offsets, and daylight-saving rules.

Tar provides the ability to create tar archives, as well as the ability to extract, update or list files in an existing archive. It is useful for combining many files into one larger file, while maintaining directory structure and file information such as permissions and creation/modification dates. GNU tar offers many extensions over the standard utility.

The which program finds the location of executables in PATH, with a variety of options. It is an alternative to the shell "type" built-in command.

This package provides all the locales supported by the GNU C Library, more than 400 in total. To use them set the LOCPATH environment variable to the share/locale sub-directory of this package.

grep is a tool for finding text inside files. Text is found by matching a pattern provided by the user in one or many files. The pattern may be provided as a basic or extended regular expression, or as fixed strings. By default, the matching text is simply printed to the screen, however the output can be greatly customized to include, for example, line numbers. GNU grep offers many extensions over the standard utility, including, for example, recursive directory searching.

GNU Coreutils package includes all of the basic command-line tools that are expected in a POSIX system, excluding shell. This package is the union of the GNU fileutils, sh-utils, and textutils packages. Most of these tools offer extended functionality beyond that which is outlined in the POSIX standard.

GNU Diffutils is a package containing tools for finding the differences between files. The "diff" command is used to show how two files differ, while "cmp" shows the offsets and line numbers where they differ. "diff3" allows you to compare three files. Finally, "sdiff" offers an interactive means to merge two files.

GNU Binutils is a collection of tools for working with binary files. Perhaps the most notable are "ld", a linker, and "as", an assembler. Other tools include programs to display binary profiling information, list the strings in a binary file, and utilities for working with archives. The "bfd" library for working with executable and object formats is also included.

Make is a program that is used to control the production of executables or other files from their source files. The process is controlled from a Makefile, in which the developer specifies how each file is generated from its source. It has powerful dependency resolution and the ability to determine when files have to be regenerated after their sources change. GNU make offers many powerful extensions over the standard utility.

This package provides all the locales supported by the GNU C Library, more than 400 in total. To use them set the LOCPATH environment variable to the share/locale sub-directory of this package.

Make is a program that is used to control the production of executables or other files from their source files. The process is controlled from a Makefile, in which the developer specifies how each file is generated from its source. It has powerful dependency resolution and the ability to determine when files have to be regenerated after their sources change. GNU make offers many powerful extensions over the standard utility.