You can use wget
to recursively download the directories you want.
wget -r --include-directories=steamos/ --directory-prefix=steamos/ --wait=15--reject=index.htm* "http://repo.steampowered.com/steamos/"
-r
tellswget
that we want to recursively download the given site.--include-directories=steamos/
limits our download to just the steamos folder, from the root of the site. Otherwise it would try to download absolutely everything from http://repo.steampowered.com/--directory-prefix=steamos/
specifies the folder this will be place in once its downloaded. By default, the download will be placed in 'repo.steampowered.com/steamos/'.--reject=index.htm*
junks the three index pages that would otherwise be saved to each sub-directory.--wait=15
places a delay of 15 seconds between your downloads, for the sake of being kind to the servers.
My main reference for this was http://learningbitsandbytes.blogspot.ca/2013/07/downloading-source-code-from-svngit.html