Very important think when you are a programmer is to have the ablility and tools to synchronize your code on multiple locations.
For example you can have a development version a test version and a production version of the code, and you will want all of these versions to be synchronized.
One way of doing that in Unix operating systems is by using the rsync command.
Rsync is a free open source project.
In order to use this command you have to install it first. This article will not go into the installation procedure. You will have to download rsync from the official site (http://samba.anu.edu.au/rsync/) and install it on your unix operating system.
Usage examples
Rsync is a very efficient command because it uses a special protocol (rsync remote-update protocol) to synchronize files. It only synchronizes the differences between files, not the all files, which makes it very fast.
The command can be used to synchronize files/folders on a local computer and between remote computers.
The command has the following syntax:
rsync [options] src dest
- options - see available options bellow
- src - This is the source path. It can be a local or remote location. This is where the files that your are going to synchronize are located.
- dest - This is the local or remote destination that you want to be synchronized with the source destination. All the files from the source destination will be copied here, and the source and destination folders will be the same.
You must specify a source and a destination, one of which may be remote.
Perhaps the best way to explain the syntax is with some examples:
- rsync *.php foo:src/
this would transfer all files matching the pattern *.php from the current directory to the directory src on the machine foo.
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- rsync -avz foo:src/my_web_site /data/tmp
this would recursively transfer all files from the directory src/my_web_site on the machine foo into the /data/tmp/my_web_site directory on the local machine. The files are transferred in “archive” mode, which ensures that symbolic links, devices, attributes, permissions, ownerships etc are preserved in the transfer. Additionally, compression will be used to reduce the size of data portions of the transfer.
-
- rsync -avz foo:src/my_web_site/ /data/tmp
a trailing slash on the source changes this behavior to transfer all files from the directory src/my_web_site on the machine foo into the /data/tmp/. A trailing / on a source name means “copy the contents of this directory”. Without a trailing slash it means “copy the directory”. This difference becomes particularly important when using the –delete option.
You can also use rsync in local-only mode.
rsync -avz *.php /home/dev/src/
The above line means synchronize all the php files from the current local directory to the “/home/dev/src/” local directory, and preserve all file/folder attributes.
The most interesting option that rsync has is the ability to use the command only to see what the diffrences are between two destinations. You can do that by sing the -n option.
rsync -navz *.php /home/dev/src/
The above line will only display the differences between the current folder and the “/home/dev/src/” folder, but it will not make any changes. This is very useful if you want to see what files you have worked on or which files were changed.
Available options
There are all the available options in rsync.
-v, --verbose increase verbosity
-q, --quiet decrease verbosity
-c, --checksum always checksum
-a, --archive archive mode
-r, --recursive recurse into directories
-R, --relative use relative path names
-b, --backup make backups (default ~ suffix)
--backup-dir make backups into this directory
--suffix=SUFFIX override backup suffix
-u, --update update only (don't overwrite newer files)
-l, --links copy symlinks as symlinks
-L, --copy-links copy the referent of symlinks
--copy-unsafe-links copy links outside the source tree
--safe-links ignore links outside the destination tree
-H, --hard-links preserve hard links
-p, --perms preserve permissions
-o, --owner preserve owner (root only)
-g, --group preserve group
-D, --devices preserve devices (root only)
-t, --times preserve times
-S, --sparse handle sparse files efficiently
-n, --dry-run show what would have been transferred
-W, --whole-file copy whole files, no incremental checks
--no-whole-file turn off --whole-file
-x, --one-file-system don't cross filesystem boundaries
-B, --block-size=SIZE checksum blocking size (default 700)
-e, --rsh=COMMAND specify rsh replacement
--rsync-path=PATH specify path to rsync on the remote machine
-C, --cvs-exclude auto ignore files in the same way CVS does
--existing only update files that already exist
--ignore-existing ignore files that already exist on the receiving side
--delete delete files that don't exist on the sending side
--delete-excluded also delete excluded files on the receiving side
--delete-after delete after transferring, not before
--ignore-errors delete even if there are IO errors
--max-delete=NUM don't delete more than NUM files
--partial keep partially transferred files
--force force deletion of directories even if not empty
--numeric-ids don't map uid/gid values by user/group name
--timeout=TIME set IO timeout in seconds
-I, --ignore-times don't exclude files that match length and time
--size-only only use file size when determining if a file should be transferred
--modify-window=NUM Timestamp window (seconds) for file match (default=0)
-T --temp-dir=DIR create temporary files in directory DIR
--compare-dest=DIR also compare destination files relative to DIR
-P equivalent to --partial --progress
-z, --compress compress file data
--exclude=PATTERN exclude files matching PATTERN
--exclude-from=FILE exclude patterns listed in FILE
--include=PATTERN don't exclude files matching PATTERN
--include-from=FILE don't exclude patterns listed in FILE
--version print version number
--daemon run as a rsync daemon
--no-detach do not detach from the parent
--address=ADDRESS bind to the specified address
--config=FILE specify alternate rsyncd.conf file
--port=PORT specify alternate rsyncd port number
--blocking-io use blocking IO for the remote shell
--no-blocking-io turn off --blocking-io
--stats give some file transfer stats
--progress show progress during transfer
--log-format=FORMAT log file transfers using specified format
--password-file=FILE get password from FILE
--bwlimit=KBPS limit I/O bandwidth, KBytes per second
--read-batch=PREFIX read batch fileset starting with PREFIX
--write-batch=PREFIX write batch fileset starting with PREFIX
-h, --help show this help screen
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