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This option is useful for transfer of large files with block-based changes or appended data, and also on systems that are disk bound, not network bound.

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Mac OS X to backup iPhoto

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language	bash

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--extended-attributes

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--extended-attributes = Copy extended attributes and resource forks.

Over SSH

rsync ....

# Rsync over the Internet
rsync --archive --verbose --compress --delete --progress -e "ssh -c arcfour -o Compression=no -x" /source/folder remotebackup@earth.com:/home/user:destination-folder 

# Rsync over LAN
# Same but disable all compression.

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--progress = Shows progress of transfer. Make sure not to use when using cron.

Command Reference

Remote file copy - Synchronize file trees across local disks, directories or across a network.

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What to copy:
 -r, --recursive             recurse into directories
 -R, --relative              use relative path names
     --exclude=PATTERN       Exclude files matching PATTERN
     --exclude-from=FILE     Read exclude patterns from FILE
 -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)
     --include=PATTERN       Don't exclude files matching PATTERN
     --include-from=FILE     Read include patterns from FILE

How to copy it:  -n, --dry-run               Perform a trial run with no changes made
 -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 links outside the destination tree
 -H, --hard-links            Preserve hard links
 -D, --devices               Preserve devices (super-user only)
 -g, --group                 Preserve group
 -o, --owner                 Preserve owner (super-user only)
 -p, --perms                 Preserve permissions
 -t, --times                 Preserve times
 -S, --sparse                Handle sparse files efficiently
 -x, --one-file-system       Don't cross filesystem boundaries
 -B, --block-size=SIZE       Force a fixed checksum block-size (default 700)
 -e, --rsh=COMMAND           Specify rsh replacement
     --rsync-path=PATH       Specify path to rsync on the remote machine
     --numeric-ids           Don't map uid/gid values by user/group name
     --timeout=TIME          Set IO timeout in seconds
 -W, --whole-file            Copy whole files, no incremental checks

Destination options:  -a, --archive               Archive mode
 -b, --backup                Make backups (see --suffix & --backup-dir)
     --backup-dir=DIR        Make backups into this directory
     --suffix=SUFFIX         Override backup suffix
 -z, --compress              Compress file data during the transfer
 -c, --checksum              Skip based on checksum, not mod-time & size
 -C, --cvs-exclude           Auto ignore files in the same way CVS does
     --existing              Only update files that already exist
     --delete                Delete files that don't exist on the sending side
     --delete-excluded       also delete excluded files on the receiving side
     --delete-after          Receiver deletes after transfer, not during
     --force                 Force deletion of directories even if not empty
     --ignore-errors         Delete even if there are IO errors
     --max-delete=NUM        Don't delete more than NUM files
     --log-format=FORMAT     Log file transfers using specified format
     --partial               Keep partially transferred files
     --progress              Show progress during transfer
 -P                          equivalent to --partial --progress
     --stats                 Give some file transfer stats
 -T  --temp-dir=DIR          Create temporary files in directory DIR
     --compare-dest=DIR      also compare destination files relative to DIR
 -u, --update                update only (don't overwrite newer files)

Misc Others:      --address=ADDRESS       bind to the specified address
     --blocking-io           Use blocking IO for the remote shell
     --bwlimit=KBPS          Limit I/O bandwidth, KBytes per second
     --config=FILE           Specify alternate rsyncd.conf file
     --daemon                Run as a rsync daemon
     --no-detach             Do not detach from the parent
     --password-file=FILE    Get password from FILE
     --port=PORT             Specify alternate rsyncd port number
 -f, --read-batch=FILE       Read batch file
 -F, --write-batch           Write batch file
     --version               Print version number
 -v, --verbose               Increase verbosity
 -q, --quiet                 Decrease verbosity
 -4, --ipv4                  Prefer IPv4
 -6, --ipv6                  Prefer IPv6
 -h, --help                  show this help screen

References

Good practical overview - http://jimmyg.org/blog/2007/rsync-basics.html

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