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Команда Rsync в Linux с примерами

rsync — это быстрая и универсальная утилита командной строки для синхронизации файлов и каталогов между двумя местоположениями через удаленную оболочку или с / на удаленный демон Rsync. Он обеспечивает быструю инкрементную передачу файлов, передавая только различия между источником и местом назначения.

Rsync можно использовать для зеркального отображения данных, инкрементного резервного копирования, копирования файлов между системами, а также в качестве замены команд scp , sftp и cp .

В этой статье объясняется, как использовать rsync на практических примерах и подробных объяснениях наиболее распространенных параметров rsync .

Установка Rsync

Утилита rsync предустановлена в большинстве дистрибутивов Linux и macOS. Если в вашей системе не установлен rsync , вы можете легко установить его с помощью диспетчера пакетов вашего дистрибутива.

Установите Rsync в Ubuntu и Debian

Установите Rsync на CentOS и Fedora

Синтаксис команды Rsync

Прежде чем перейти к использованию команды rsync , давайте начнем с обзора основного синтаксиса.

Выражения утилиты rsync имеют следующую форму:

• OPTION — параметры rsync .
• SRC — Исходный каталог.
• DEST — целевой каталог.
• USER — удаленное имя пользователя.
• HOST — удаленное имя хоста или IP-адрес.

rsync предоставляет ряд параметров, управляющих поведением команды. Наиболее широко используемые варианты:

• -a , —archive , режим архива, эквивалент -rlptgoD . Этот параметр указывает rsync рекурсивно синхронизировать каталоги, передавать специальные и блочные устройства, сохранять символические ссылки, время модификации, группы, владение и разрешения.
• -z , —compress . Эта опция заставляет rsync сжимать данные при их отправке на конечный компьютер. Используйте эту опцию, только если подключение к удаленному компьютеру медленное.
• -P , что эквивалентно —partial —progress . Когда используется эта опция, rsync показывает индикатор выполнения во время передачи и сохраняет частично переданные файлы. Это полезно при передаче больших файлов по медленным или нестабильным сетевым соединениям.
• —delete . Когда используется эта опция, rsync удаляет посторонние файлы из места назначения. Это полезно для зеркалирования.
• -q , —quiet . Используйте эту опцию, если вы хотите подавить сообщения, не связанные с ошибками.
• -e . Эта опция позволяет вам выбрать другую удаленную оболочку. По умолчанию rsync настроен на использование ssh.

Базовое использование Rsync

Самый простой вариант использования rsync — это копирование одного файла из одного в другое локальное расположение. Вот пример:

Пользователь, выполняющий команду, должен иметь разрешения на чтение в исходном местоположении и разрешения на запись в месте назначения.

Если пропустить имя файла из места назначения, файл будет скопирован с текущим именем. Если вы хотите сохранить файл под другим именем, укажите новое имя в целевой части:

Настоящая мощь rsync проявляется в синхронизации каталогов. В приведенном ниже примере показано, как создать локальную резервную копию файлов веб-сайта:

Если целевой каталог не существует, rsync создаст его.

Стоит отметить, что rsync разному обрабатывает исходные каталоги с помощью завершающей косой черты ( / ). Если исходный каталог имеет косую черту в конце, команда скопирует только содержимое каталога в целевой каталог. Если косая черта в конце опущена, rsync копирует исходный каталог в целевой каталог.

Использование rsync для синхронизации данных с / на удаленную машину

При использовании rsync для удаленной передачи данных его необходимо установить как на исходном, так и на целевом компьютере. Новые версии rsync настроены на использование SSH в качестве удаленной оболочки по умолчанию.

В следующем примере мы переносим каталог с локального компьютера на удаленный:

Чтобы передать данные с удаленного компьютера на локальный, используйте удаленное местоположение в качестве источника:

Если SSH на удаленном хосте прослушивает порт, отличный от порта по умолчанию 22, укажите порт с помощью параметра -e :

При передаче больших объемов данных рекомендуется запускать команду rsync внутри сеанса экрана или использовать параметр -P :

Исключить файлы и каталоги

Есть два варианта исключения файлов и каталогов. Первый вариант — использовать аргумент —exclude и указать файлы и каталоги, которые вы хотите исключить, в командной строке.

При исключении файлов или каталогов необходимо использовать их относительные пути к исходному местоположению.

В следующем примере показано, как исключить node_modules и tmp :

Второй вариант — использовать параметр —exclude-from и указать файлы и каталоги, которые вы хотите исключить из файла.

Выводы

Мы показали вам, как использовать Rsync для копирования и синхронизации файлов и каталогов. Еще больше информации о Rsync можно найти на странице руководства пользователя Rsync .

Не стесняйтесь оставлять комментарии, если у вас есть вопросы.

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rsync

rsync is an open source utility that provides fast incremental file transfer.

Contents

Installation

rsync must be installed on both the source and the destination machine.

Front-ends

• Grsync — GTK front-end.

https://www.opbyte.it/grsync/ || grsync

• gutback — rsync wrapper written in Shell.

https://github.com/gutenye/gutbackup || gutbackupAUR

• JotaSync — Java Swing GUI for rsync with integrated scheduler.

https://trixon.se/projects/jotasync/ || jotasyncAUR

• luckyBackup — Qt front-end written in C++.

http://luckybackup.sourceforge.net/index.html || luckybackupAUR

Other tools using rsync are rdiff-backup and osync AUR .

As cp/mv alternative

rsync can be used as an advanced alternative for the cp or mv command, especially for copying larger files:

The -P option is the same as —partial —progress , which keeps partially transferred files and shows a progress bar during transfer.

You may want to use the -r / —recursive option to recurse into directories.

Files can be copied locally as with cp, but the motivating purpose of rsync is to copy files remotely, i.e. between two different hosts. Remote locations can be specified with a host-colon syntax:

Network file transfers use the SSH protocol by default and host can be a real hostname or a predefined profile/alias from .ssh/config .

Whether transferring files locally or remotely, rsync first creates a file-list containing information (by default, it is the file size and last modification timestamp) which will then be used to determine if a file needs to be constructed. For each file to be constructed, a weak and strong checksum is found for all blocks such that each block is of length S bytes, non-overlapping, and has an offset which is divisible by S. Using this information a large file can be constructed using rsync without having to transfer the entire file. For a more detailed practical explanation and detailed mathematical explanation refer to how rsync works and the rsync algorithm, respectively.

To use sane defaults quickly, you could use some aliases:

Trailing slash caveat

Arch by default uses GNU cp (part of GNU coreutils ). However, rsync follows the convention of BSD cp, which gives special treatment to source directories with a trailing slash «/». Although

creates a directory «destination/source» with the contents of «source», the command

copies all of the files in «source/» directly into «destination», with no intervening subdirectory — just as if you had invoked it as

This behavior is different from that of GNU cp, which treats «source» and «source/» identically (but not «source/.»). Also, some shells automatically append the trailing slash when tab-completing directory names. Because of these factors, there can be a tendency among new or occasional rsync users to forget about rsync’s different behavior, and inadvertently create a mess or even overwrite important files by leaving the trailing slash on the command line.

Thus it can be prudent to use a wrapper script to automatically remove trailing slashes before invoking rsync:

This script can be put somewhere in the path, and aliased to rsync in the shell init file.

As a backup utility

The rsync protocol can easily be used for backups, only transferring files that have changed since the last backup. This section describes a very simple scheduled backup script using rsync, typically used for copying to removable media.

Automated backup

For the sake of this example, the script is created in the /etc/cron.daily directory, and will be run on a daily basis if a cron daemon is installed and properly configured. Configuring and using cron is outside the scope of this article.

First, create a script containing the appropriate command options:

-a indicates that files should be archived, meaning that most of their characteristics are preserved (but not ACLs, hard links or extended attributes such as capabilities) —delete means files deleted on the source are to be deleted on the backup as well

Here, /path/to/backup should be changed to what needs to be backed-up (e.g. /home ) and /location/of/backup is where the backup should be saved (e.g. /media/disk ).

Finally, the script must be executable:

Automated backup with SSH

If backing-up to a remote host using SSH, use this script instead:

-e ssh tells rsync to use SSH remoteuser is the user on the host remotehost -a groups all these options -rlptgoD (recursive, links, perms, times, group, owner, devices)

Automated backup with NetworkManager

This script starts a backup when network connection is established.

First, create a script containing the appropriate command options:

-a group all this options -rlptgoD recursive, links, perms, times, group, owner, devices —files-from read the relative path of /path/to/backup from this file —bwlimit limit I/O bandwidth; KBytes per second

Automated backup with systemd and inotify

Instead of running time interval backups with time based schedules, such as those implemented in cron, it is possible to run a backup every time one of the files you are backing up changes. systemd.path units use inotify to monitor the filesystem, and can be used in conjunction with systemd.service files to start any process (in this case your rsync backup) based on a filesystem event.

First, create the systemd.path file that will monitor the files you are backing up:

Then create a systemd.service file that will be activated when it detects a change. By default a service file of the same name as the path unit (in this case backup.path ) will be activated, except with the .service extension instead of .path (in this case backup.service ).

Now all you have to do is start/enable backup.path like a normal systemd service and it will start monitoring file changes and automatically start backup.service .

Differential backup on a week

This is a useful option of rsync, resulting in a full backup (on each run) and keeping a differential backup copy of changed files only in a separate directory for each day of a week.

First, create a script containing the appropriate command options:

—inplace implies —partial update destination files in-place

Snapshot backup

The same idea can be used to maintain a tree of snapshots of your files. In other words, a directory with date-ordered copies of the files. The copies are made using hardlinks, which means that only files that did change will occupy space. Generally speaking, this is the idea behind Apple’s TimeMachine.

This basic script is easy to implement and creates quick incremental snapshots using the —link-dest option to hardlink unchanged files:

There must be a symlink to a full backup already in existence as a target for —link-dest . If the most recent snapshot is deleted, the symlink will need to be recreated to point to the most recent snapshot. If —link-dest does not find a working symlink, rsync will proceed to copy all source files instead of only the changes.

A more sophisticated version keeps an up-to-date full backup $SNAP/latest and in case a certain number of files has changed since the last full backup, it creates a snapshot $SNAP/$DATETAG of the current full-backup utilizing cp -al to hardlink unchanged files:

To make things really, really simple this script can be run from a systemd/Timers unit.

Full system backup

This section is about using rsync to transfer a copy of the entire / tree, excluding a few selected directories. This approach is considered to be better than disk cloning with dd since it allows for a different size, partition table and filesystem to be used, and better than copying with cp -a as well, because it allows greater control over file permissions, attributes, Access Control Lists and extended attributes.

rsync will work even while the system is running, but files changed during the transfer may or may not be transferred, which can cause undefined behavior of some programs using the transferred files.

This approach works well for migrating an existing installation to a new hard drive or SSD.

Run the following command as root to make sure that rsync can access all system files and preserve the ownership:

By using the -aAX set of options, the files are transferred in archive mode which ensures that symbolic links, devices, permissions, ownerships, modification times, ACLs, and extended attributes are preserved, assuming that the target file system supports the feature. The option -H preserves hard links, but uses more memory.

The —exclude option causes files that match the given patterns to be excluded. The directories /dev , /proc , /sys , /tmp , and /run are included in the above command, but the contents of those directories are excluded. This is because they are populated on boot, but the directories themselves are not created. /lost+found is filesystem-specific. The command above depends on brace expansion available in both the bash and zsh shells. When using a different shell, —exclude patterns should be repeated manually. Quoting the exclude patterns will avoid expansion by the shell, which is necessary, for example, when backing up over SSH. Ending the excluded paths with * ensures that the directories themselves are created if they do not already exist.

You may want to include additional rsync options, or remove some, such as the following. See rsync(1) for the full list.

• If you run on a system with very low memory, consider removing -H option; however, it should be no problem on most modern machines. There can be many hard links on the file system depending on the software used (e.g. if you are using Flatpak). Many hard links reside under the /usr/ directory.
• You may want to add rsync’s —delete option if you are running this multiple times to the same backup directory. In this case make sure that the source path does not end with /* , or this option will only have effect on the files inside the subdirectories of the source directory, but it will have no effect on the files residing directly inside the source directory.
• If you use any sparse files, such as virtual disks, Docker images and similar, you should add the -S option.
• The —numeric-ids option will disable mapping of user and group names; instead, numeric group and user IDs will be transfered. This is useful when backing up over SSH or when using a live system to backup different system disk.
• Choosing —info=progress2 option instead of -v will show the overall progress info and transfer speed instead of the list of files being transferred.
• To avoid crossing a filesystem boundary when recursing, add the option -x / —one-file-system . This will prevent backing up any mount point in the hierarchy.

Restore a backup

If you wish to restore a backup, use the same rsync command that was executed but with the source and destination reversed.

File system cloning

rsync provides a way to do a copy of all data in a file system while preserving as much information as possible, including the file system metadata. It is a procedure of data cloning on a file system level where source and destination file systems do not need to be of the same type. It can be used for backing up, file system migration or data recovery.

rsync’s archive mode comes close to being fit for the job, but it does not back up the special file system metadata such as access control lists, extended attributes or sparse file properties. For successful cloning at the file system level, some additional options need to be provided:

And their meaning is (from the manpage):

Additionally, use -x if you have other filesystems mounted under the tree that you want to exclude from the copy. Produced copy can be simply reread and checked (for example after a data recovery attempt) at the file system level with diff ‘s recursive option:

It is possible to do a successful file system migration by using rsync as described in this article and updating the fstab and bootloader as described in Migrate installation to new hardware. This essentially provides a way to convert any root file system to another one.

rsync daemon

rsync can be run as daemon on a server listening on port 873 .

Edit the template /etc/rsyncd.conf , configure a share and start the rsyncd.service .

Usage from client, e.g. list server content:

transfer file from client to server:

Consider iptables to open port 873 and user authentication.

Example configuration

Sharing from a list of files

Inside the file list, all the intermediary paths are necessary, except when the *** wildcard is used:

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