Rsync is a great tool – incredibly powerful for synchronizing directories, copying over a network or over SSH, an awesome way to backup a mobile device back to a core network securely and other great functions. it works better than just about anything else developed before or since, but is a command line UI that is easy to forget if you don’t use it for a while and Windows is a challenge.
This isn’t meant to be a comprehensive guide, they’re are lots of those, but a quick summary of what I find useful.
There’s one confusing thing that I have to check often to be sure it is going to do what I think it should – the trailing slash on the source. It works like this:
A quick summary of useful command options (there are many, many) is:
-v, --verbose increase verbosity -r, --recursive recursive (go into subdirectories) -c, --checksum skip based on checksum, not mod-time & size (slow, but accurate) -a, --archive archive mode; equals -rlptgoD (no -H,-A,-X) (weird with SMB/CIFS) -z, --compress compress file data during the transfer, should help over slow links -n, --dry-run trial run, don't move anything -h, --human-readable display the output numbers in a human-readable format -u, --update only copy files that have different sizes and equal or later modification times (-c will enable checksum comparison) --progress show the sync progress during transfer --exclude ".*" exclude files starting with "." --remove-source-files after synced, empty the dir (like mv/merge) --delete any files in dest that aren't in source are deleted in destination (danger) --info=progress2 --info=name0 This yields a pretty usable one line progress meter.
I do not recommend using compression (
-z) on a LAN, it’ll probably slow you down. Over a slower (typically) WAN link it usually helps, but YMMV depending on link and CPU speed. Test it with that one line progress meter if it is a long enough sync to matter – it shows transfer rate a little like this:
1,770,984,121 2% 747.54kB/s 27:46:38 xfr#2159, ir-chk=1028/28648)
If the files really have to be accurately transferred, the checksum (
-c) option is critical – every copy (or at least “move”) function should include this validation, especially before deleting the original.