Keep one BIG file in sync

Joseph Annino jannino at
Fri Feb 22 15:28:50 EST 2002

This is cool.  You can't really tell that this is what is going on from
reading the man page.

On 2/21/02 10:55 PM, "Tom Diehl" <tdiehl at> wrote:

> On Thu, 21 Feb 2002, Joseph Annino wrote:
>> But I thought rsync will always copy the complete file, not just the
>> differences.  So the checksums are for the complete file, and if the
>> complete file checksum doesn't match, the complete file is transferred.
>> That isn't whats desired here, just the differences WITHIN a file.
>> If my understanding is wrong and rsync does have the proper magic to copy
>> just the differences within a file then rsync is even cooler than I thought.
> That is the magic of rsync and why I can keep 80 gigs of data in sync over
> a realitively small dsl line. My first encounters with rsync allowed me to
> keep
> 200+ megs of data in syne over a dial up.
> If you want the gorey details of just how it works go here:
> and read his thesis. A lot of it is wayyyyyyyyy
> over my head but I got the gist of it. This was the first time I really
> understood just how cool rsync is.
> FWIW one of the really neat tricks is to download iso images and find out
> that for what ever reason they are corrupt. rsync will happly fix them for
> you. Another thing I use it for is keeping our ftp site in sync. When
> a new Redhat distro comes out rather than dload the whole thing I just
> copy the last distro to the new tree and rsync just dloads the diffs.
> Rsync tis a wonderful program. :-))))))))
> HTH,

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