Dosage is an application designed to keep a local copy of specific webcomics
and other picture-based content such as Picture of the Day sites. With the
dosage commandline script you can get the latest strip of a webcomic, or
catch-up to the last strip downloaded, or download a strip for a particular
date/index (if the webcomic's site layout allows this).

WWW: http://wummel.github.io/dosage/