The web can be used as a special remote too.

# git annex addurl http://example.com/video.mpeg
addurl example.com_video.mpeg (downloading http://example.com/video.mpeg)
########################################################## 100.0%
ok

Now the file is downloaded, and has been added to the annex like any other file. So it can be renamed, copied to other repositories, and so on.

To add a lot of urls at once, just list them all as parameters to git annex addurl.

trust issues

Note that git-annex assumes that, if the web site does not 404, and has the right file size, the file is still present on the web, and this counts as one copy of the file. If the file still seems to be present on the web, it will let you remove your last copy, trusting it can be downloaded again:

# git annex drop example.com_video.mpeg
drop example.com_video.mpeg (checking http://example.com/video.mpeg) ok

If you don't trust the web to this degree, just let git-annex know:

# git annex untrust web
untrust web ok

With the result that it will hang onto files:

# git annex drop example.com_video.mpeg
drop example.com_video.mpeg (unsafe) 
  Could only verify the existence of 0 out of 1 necessary copies
  Also these untrusted repositories may contain the file:
    00000000-0000-0000-0000-000000000001  -- web
  (Use --force to override this check, or adjust numcopies.)
failed

attaching urls to existing files

You can also attach urls to any file already in the annex:

# git annex addurl --file my_cool_big_file http://example.com/cool_big_file
addurl my_cool_big_file ok
# git annex whereis my_cool_big_file
whereis my_cool_big_file (2 copies) 
00000000-0000-0000-0000-000000000001 -- web
27a9510c-760a-11e1-b9a0-c731d2b77df9 -- here

configuring filenames

By default, addurl will generate a filename for you. You can use --file= to specify the filename to use.

If you're adding a bunch of related files to a directory, or just don't like the default filenames generated by addurl, you can use --pathdepth to specify how many parts of the url are put in the filename. A positive number drops that many paths from the beginning, while a negative number takes that many paths from the end.

# git annex addurl http://example.com/videos/2012/01/video.mpeg
addurl example.com_videos_2012_01_video.mpeg (downloading http://example.com/videos/2012/01/video.mpeg)
# git annex addurl http://example.com/videos/2012/01/video.mpeg --pathdepth=2
addurl 2012_01_video.mpeg (downloading http://example.com/videos/2012/01/video.mpeg)
# git annex addurl http://example.com/videos/2012/01/video.mpeg --pathdepth=-2
addurl 01_video.mpeg (downloading http://example.com/videos/2012/01/video.mpeg)

videos

There's support for downloading videos from sites like YouTube, Vimeo, and many more. This relies on quvi to find urls to the actual videos files.

When you have quvi installed, you can just git annex addurl http://youtube.com/foo and it will detect that it is a video and download the video content for offline viewing.

Later, in another clone of the repository, you can run git annex get on the file and it will also be downloaded with the help of quvi. This works even if the video host has transcoded or otherwise changed the video in the meantime; the assumption is that these video files are equivalent.

There is an annex.quvi-options configuration setting that can be used to pass parameters to quvi. For example, you could set git config annex.quvi-options "--format low" to configure it to download low quality videos from YouTube.

Note that for performance reasons, the url is not checked for redirects, so some shortened urls will not be detected. You can either load the short url in a browser to get the full url, or you can force use of quvi with redirect detection, by prepending "quvi:" to the url.

To download a youtube playlist, you need to find the feed associated with that playlist, and pass it to git annex importfeed. There does not seem to be an easy link anywhere to get the feed, but you can construct its url manually. For a playlist like "https://www.youtube.com/playlist?list=PL4F80C7D2DC8D9B6C", the feed is "http://gdata.youtube.com/feeds/api/playlists/PL4F80C7D2DC8D9B6C"

More details about youtube feeds at http://googlesystem.blogspot.com/2008/01/youtube-feeds.html -- git-annex importfeed should handle all of them.

bittorrent

The bittorrent special remote lets git-annex also download the content of torrent files, and magnet links to torrents.

You can simply pass the url to a torrent to git annex addurl the same as any other url.

You have to have aria2 and bittornado (or the original bittorrent) installed for this to work.

podcasts

This is done using git annex importfeed. See downloading podcasts.