First, install it, using apt, yum, pacman, etc.
Imagine we want to back up files from Directory1 to Directory2, and both are on the same hard drive (this would work the same if the directories are on two different drives). There are several different ways to do this, depending on what kind of backups (i.e., options you want to give rsync) you want to configure. The most general, will be this:
$ rsync -av --delete /Directory1/ /Directory2/The code will sync the contents of Directory1 to Directory2, leaving no differences between the two. If rsync finds that Directory2 has a file that Directory1 does not, it will delete it. If rsync finds a file that has been changed, created, or deleted in Directory1, it will reflect those same changes to Directory2.
The options passed to rsync are the following (more can be found at the end):
- -a = archive. Means several things: recursive (recurse into directories), links (copy symlinks as symlinks), perms (preserve permissions), times (preserve modification times), group (preserve group), owner (preserve owner), preserve device files, and preserve special files.
- -v = verbose. You can see what rsync is backing up.
- –delete = Deletes any files in Directory2 that aren’t in Directory1.
If you don't want to make a perfect copy/backup of the folder, but instead add everything that rsync finds in the source folder, don't use the --delete option.
Different ways of using rysnc for external backups are possible. The easiest and most secure method is tunneling rsync through SSH. Most servers and even many clients already have SSH, and it can be used for your rsync backups. The process is described for machines on a local network, but this would be the exact same one if one host were out on the internet somewhere (note that port 22, or whatever port you have SSH configured on, would need to be forwarded on any network equipment on the server’s side of things).
You need ssh installed in the computer.
(Note: you only need rsync and ssh, setup the repositories on the server where you would like the files backed up, and make sure that SSH is locked down. Make sure the user you plan on using has a complex password, and it may also be a good idea to switch the port that SSH listens on--default is 22.)
The command is the same, but a few additionas are needed. For user “john” connecting to “192.168.235.137” and using the same options as above (-av –delete) we run the following:
$ rsync -av –delete -e ssh /Directory1/ [email protected]:/Directory2/If you have changed the port (maybe to '12345'), take that into account when calling ssh:
$ rsync -av –delete -e 'ssh -p 12345' /Directory1/ [email protected]:/Directory2/Cron can be used to automate the execution of commands on the background. Using it, we can run nightly backups, or however often you would like them to run.
Firstly, you have to edit the cron table:
$ crontab -eIts syntax its a bit messy (man crontab does not help much, so check www.crontab.guru or other webpage), for example:
- To run rsync command every night at 10 PM
0 22 * * * rsync -av --delete /Directory1/ /Directory2/The first “0” specifies the minute of the hour, and “22” specifies 10 PM. Since we want this command to run daily, we will leave the rest of the fields with asterisks and then paste the rsync command.
Or,
15 3 * * 1-5 rync -av /Users/john/Documents /Volumes/External_HDD/office_backup/to run a nigthly backup, at 3:15am, inside an external hard-drive that is connected to the computer.
Or,
15 3 * * 1-5 rync -av -e ssh /Users/john/Work alias_office:/Volumes/External_HDD/office_backup/to run a nightly backup over ssh to an external hard-drive connected yo your office (you have created an alias for you office in .ssh/config file)
To check which cron jobs have been scheduled in crontab, you can type crontab -l. If you want to delete all of them, crontab -r.
I usually work with a desktop and a laptop, with the former having an external hard-drive connected to it, where I do all my backups. The desktop has a cron jobs running in the background and making nightly copies of certain folders. I also want to backup the laptop from home, so I created an alias in my .bashrc file, to backup with rsync over ssh.
To create an alias in you .bash_profile or .bashrc file, the syntax is as follows:
alias backup_docs="rsync -av -e ssh ~/Documents/Folder1 alias_office:/Volumes/External_HDD/laptop_backup/"You can even schedule you laptop to wake up at night, do the back up and then turn off again.
I want to keep a monthly backup in case a disaster occurs and I have to restore. I want this to not occupy much space, so I will create a compressed file. To do this, I will use the tar command.
The tar command needs a few options:
- c – Creates a new .tar archive file.
- v – Verbosely show the .tar file progress.
- f – File name type of the archive file.
I want the highest compression, so I will be using the bz2 feature, which compress and create archive files less than the size of the gzip, in contrast compression takes more time to compress and decompress files. To create highly compressed tar file, use option as -j.
My idea is to make a backup, every month, but not overwrite what I had before. This is specially important if you use the --delete flag when using rsync. You can name the file monthly_$(date +%Y%m%d).tar.bz2 where the bash regular expression will introduce the year, month and day in the name of the file.
You can create a cron job that will run every first day of the month, at 4:30am, using the following:
30 4 1 * * tar -cvjf /Volumes/External_HDD/office_backup/monthly/monthly_$(date +%Y%m%d).tar.bz2 /Volumes/External_HDD/office_backup/daily(Note: the tar command has a different syntax with respect rsync: you have to put first the "destination" (which is the file to be created) and then the folder to be compressed.
This is the same process, but you have to decompress the backup file and copy it to the destination. You don't need a cron job to this (or I don't think so, but maybe you do).
$ rsync -aAXv --delete --exclude="lost+found" where/you/keep/your/backup where/your/backup/should/beThe options and the excluded files are different for my hard-drive configuration.
Rsync options:
-v, --verbose increase verbosity
-q, --quiet suppress non-error messages
--no-motd suppress daemon-mode MOTD (see caveat)
-c, --checksum skip based on checksum, not mod-time & size
-a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)
--no-OPTION turn off an implied OPTION (e.g. --no-D)
-r, --recursive recurse into directories
-R, --relative use relative path names
--no-implied-dirs don’t send implied dirs with --relative
-b, --backup make backups (see --suffix & --backup-dir)
--backup-dir=DIR make backups into hierarchy based in DIR
--suffix=SUFFIX backup suffix (default ~ w/o --backup-dir)
-u, --update skip files that are newer on the receiver
--inplace update destination files in-place
--append append data onto shorter files
--append-verify --append w/old data in file checksum
-d, --dirs transfer directories without recursing
-l, --links copy symlinks as symlinks
-L, --copy-links transform symlink into referent file/dir
--copy-unsafe-links only "unsafe" symlinks are transformed
--safe-links ignore symlinks that point outside the tree
-k, --copy-dirlinks transform symlink to dir into referent dir
-K, --keep-dirlinks treat symlinked dir on receiver as dir
-H, --hard-links preserve hard links
-p, --perms preserve permissions
-E, --executability preserve executability
--chmod=CHMOD affect file and/or directory permissions
-A, --acls preserve ACLs (implies -p)
-X, --xattrs preserve extended attributes
-o, --owner preserve owner (super-user only)
-g, --group preserve group
--devices preserve device files (super-user only)
--specials preserve special files
-D same as --devices --specials
-t, --times preserve modification times
-O, --omit-dir-times omit directories from --times
--super receiver attempts super-user activities
--fake-super store/recover privileged attrs using xattrs
-S, --sparse handle sparse files efficiently
-n, --dry-run perform a trial run with no changes made
-W, --whole-file copy files whole (w/o delta-xfer algorithm)
-x, --one-file-system don’t cross filesystem boundaries
-B, --block-size=SIZE force a fixed checksum block-size
-e, --rsh=COMMAND specify the remote shell to use
--rsync-path=PROGRAM specify the rsync to run on remote machine
--existing skip creating new files on receiver
--ignore-existing skip updating files that exist on receiver
--remove-source-files sender removes synchronized files (non-dir)
--del an alias for --delete-during
--delete delete extraneous files from dest dirs
--delete-before receiver deletes before transfer (default)
--delete-during receiver deletes during xfer, not before
--delete-delay find deletions during, delete after
--delete-after receiver deletes after transfer, not before
--delete-excluded also delete excluded files from dest dirs
--ignore-errors delete even if there are I/O errors
--force force deletion of dirs even if not empty
--max-delete=NUM don’t delete more than NUM files
--max-size=SIZE don’t transfer any file larger than SIZE
--min-size=SIZE don’t transfer any file smaller than SIZE
--partial keep partially transferred files
--partial-dir=DIR put a partially transferred file into DIR
--delay-updates put all updated files into place at end
-m, --prune-empty-dirs prune empty directory chains from file-list
--numeric-ids don’t map uid/gid values by user/group name
--timeout=SECONDS set I/O timeout in seconds
--contimeout=SECONDS set daemon connection timeout in seconds
-I, --ignore-times don’t skip files that match size and time
--size-only skip files that match in size
--modify-window=NUM compare mod-times with reduced accuracy
-T, --temp-dir=DIR create temporary files in directory DIR
-y, --fuzzy find similar file for basis if no dest file
--compare-dest=DIR also compare received files relative to DIR
--copy-dest=DIR ... and include copies of unchanged files
--link-dest=DIR hardlink to files in DIR when unchanged
-z, --compress compress file data during the transfer
--compress-level=NUM explicitly set compression level
--skip-compress=LIST skip compressing files with suffix in LIST
-C, --cvs-exclude auto-ignore files in the same way CVS does
-f, --filter=RULE add a file-filtering RULE
-F same as --filter=’dir-merge /.rsync-filter’
repeated: --filter=’- .rsync-filter’
--exclude=PATTERN exclude files matching PATTERN
--exclude-from=FILE read exclude patterns from FILE
--include=PATTERN don’t exclude files matching PATTERN
--include-from=FILE read include patterns from FILE
--files-from=FILE read list of source-file names from FILE
-0, --from0 all *from/filter files are delimited by 0s
-s, --protect-args no space-splitting; wildcard chars only
--address=ADDRESS bind address for outgoing socket to daemon
--port=PORT specify double-colon alternate port number
--sockopts=OPTIONS specify custom TCP options
--blocking-io use blocking I/O for the remote shell
--stats give some file-transfer stats
-8, --8-bit-output leave high-bit chars unescaped in output
-h, --human-readable output numbers in a human-readable format
--progress show progress during transfer
-P same as --partial --progress
-i, --itemize-changes output a change-summary for all updates
--out-format=FORMAT output updates using the specified FORMAT
--log-file=FILE log what we’re doing to the specified FILE
--log-file-format=FMT log updates using the specified FMT
--password-file=FILE read daemon-access password from FILE
--list-only list the files instead of copying them
--bwlimit=KBPS limit I/O bandwidth; KBytes per second
--write-batch=FILE write a batched update to FILE
--only-write-batch=FILE like --write-batch but w/o updating dest
--read-batch=FILE read a batched update from FILE
--protocol=NUM force an older protocol version to be used
--iconv=CONVERT_SPEC request charset conversion of filenames
--checksum-seed=NUM set block/file checksum seed (advanced)
-4, --ipv4 prefer IPv4
-6, --ipv6 prefer IPv6
--version print version number
(-h) --help show this help (see below for -h comment)
Rsync can also be run as a daemon, in which case the following options are accepted:
Rsync can also be run as a daemon, in which case the following options are accepted:
--daemon run as an rsync daemon
--address=ADDRESS bind to the specified address
--bwlimit=KBPS limit I/O bandwidth; KBytes per second
--config=FILE specify alternate rsyncd.conf file
--no-detach do not detach from the parent
--port=PORT listen on alternate port number
--log-file=FILE override the "log file" setting
--log-file-format=FMT override the "log format" setting
--sockopts=OPTIONS specify custom TCP options
-v, --verbose increase verbosity
-4, --ipv4 prefer IPv4
-6, --ipv6 prefer IPv6
-h, --help show this help (if used after --daemon)
- Credits to https://www.howtogeek.com/135533/how-to-use-rsync-to-backup-your-data-on-linux/ and https://jonsuh.com/blog/bash-command-line-shortcuts/, http://www.mikerubel.org/computers/rsync_snapshots/, https://www.marksanborn.net/howto/use-rsync-for-daily-weekly-and-full-monthly-backups/, https://averagelinuxuser.com/backup-and-restore-your-linux-system-with-rsync/, https://www.tecmint.com/18-tar-command-examples-in-linux/, for some of the info.
- If you want to learn more about how rsync works, check https://rsync.samba.org/how-rsync-works.html