You may had the situation yourself, you have a huge file beeing transfered via scp and suddenly the connection drops. It would be cool if one could resume the transfer, so you do not have to transfer the whole file again but only what is missing on your end.

You can do that with rsync.

For example you did run the follwoing scp command:

scp bob@aliceserver.org:/data/huge.tar.gz

Then you can resume the transfer with rsync like this:

rsync -P -rsh=ssh bob@aliceserver.org:/data/huge.tar.gz ./huge.tar.gz

Cool, isn’t it?