Download Changes
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When testing daily ISO images, it is useful to only download the parts of the ISO that has changed since the previous days. That way we can preserve time and bandwidth.
Rsync method
This approach requires server-side support, and a lot of flags specified.
rsync --times \
--compress --partial \
--progress --stats \
--human-readable \
--human-readable \
rsync://cdimage.ubuntu.com/cdimage/kubuntu/daily-live/20200412/focal-desktop-amd64.iso \
kubuntu-focal-desktop-amd64.iso
| Flag | Description |
|---|---|
--times |
Transfer modification times along with the files. |
--compress |
Compress the file data during transit. |
--partial |
Keep partial downloads if interrupted. |
--progress |
Print information showing the progress of the /transfer. |
--stats |
Print a set of statistics on the file transfer. |
--human-readable |
Output numbers in a more human readable format, can use up to 3 times. |
Zsync method
This approach does not involve adding a bunch of flags, but it does require the provider to have a .zsync file on their server and for the user to have the zync package installed. This package typically isn’t installed by default on most systems.
zsync http://cdimage.ubuntu.com/kubuntu/daily-live/20200412/focal-desktop-amd64.iso.zsync