wget or rsync

[Xplorer4x4]

I am writing a bash script/cronjob that will check a remote file url once a day and grab the file if it differs from the one currently in my dropbox folder. It seems wget or rsync would both work for this task, but I am curious to see which tool is better for the job in my specific case(and generally speaking as well) and why? The remote file is under 10 MB and considering it is an android app, I do not see it growing to over 10 MB any time soon unless some crazy radical new feature gets added. Even then, again, we are talking about an android app, so the size should remain relatively small in any case.

[SteveRiley]

I'm curious...wouldn't Dropbox's own sync feature take care of that for you?

[Xplorer4x4]

Not that I am aware of. Dropbox can grab the file via an http url and upload it to dropbox?

On further examination, it doesn’t seem rsync can retrieve a file via http can it? Did I miss something here as well?

[SteveRiley]

Sorry -- I fell victim of reading your post too quickly. I see now that you're fetching from someplace that is not Dropbox-aware.

rsync, on its own, can't use HTTP. However, zsync can. I suspect this will work for you. Its advantage over wget is that it implements the rsync protocol inside HTTP, meaning it downloads only the changed portions of files. wget can't do that. Plus, it's in the *buntu repository.

steve@t520:~$ [B]apt-cache show zsync[/B]
Package: zsync
Priority: optional
Section: universe/net
Installed-Size: 245
Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
Original-Maintainer: Robert Lemmen <robertle@semistable.com>
Architecture: amd64
Version: 0.6.2-1ubuntu1
Depends: libc6 (>= 2.15)
Filename: pool/universe/z/zsync/zsync_0.6.2-1ubuntu1_amd64.deb
Size: 115036
MD5sum: d3eb1d12ee24ab25080c7741e3e52be3
SHA1: f07682cccbec4a2f13e7d1ce43f9c6437c3ef94f
SHA256: d68fa56816e78028e9c383d39979664b86278c61e64f99096454e3c974a83e3c
Description-en: client-side implementation of the rsync algorithm
 zsync is a file transfer program to download files from
 remote web servers. If a previous version of a file is available
 locally, zsync will only download changed parts and hereby
 minimise the download volume. The algorithm is the same as used
 by rsync(1), but zsync does not require any server software
 (apart from a web server), nor does it need shell access.
 Instead, it uses a control file (.zsync file) that describes the
 file to be downloaded, which it uses to determine the blocks to
 fetch. This file is created once on the server (and not for each
 request) and sits next to actual file to download
Homepage: http://zsync.moria.org.uk/                                                                                                                                                     
Description-md5: 55c7895466b4c20f2f56e9be9a5d33c4                                                                                                                                        
Bugs: https://bugs.launchpad.net/ubuntu/+filebug                                                                                                                                         
Origin: Ubuntu

[Xplorer4x4]

Well I figure it is probably a good idea to keep the last 3 versions of apk in case the latest one or two is buggy. FYI, I am referring to Titanium Backup as the android app. Thanks for the tip on zsync though. Looking in to it now.