EZ rsync cheat sheet

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.