RSS feed reader with sample data

#current syntax in use to grab media URL
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url=`echo "$r" | grep -e "${parse}" | sed -e 's/ /\n/g' | grep -e "${tag}" | grep -e "${format}" | sed -e 's/.*http//' -e 's/'${format}'\$.*//' | sed -e 's/'${format}'.*//'`
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data set 1
r="<p>Download: <a href="http://blip.tv/file/get/Thisoldnerd-HomeTheaterComponentsTheEpicSetupThisOldNerdS02E10HD173.m4v">HD (m4v)</a> | <a href="http://blip.tv/file/get/Thisoldnerd-HomeTheaterComponentsTheSetupThisOldNerdS02E10HDMP4669.mp4">HD (mp4)</a> | <a href="http://blip.tv/file/get/Thisoldnerd-HomeTheaterComponentsTheSetupThisOldNerdS02E10130.mp4">SD (mp4)</a> | <a href="http://blip.tv/file/get/Thisoldnerd-HomeTheaterComponentsTheEpicSetupThisOldNerdS02E10Tin459.mp4">Tiny (mp4)</a></p>"

tag="href="
parse="<p>Download:"
format="m4v"
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data set 2
r="<enclosure url="http://www.podtrac.com/pts/redirect.mp4/podcast.g4tv.com/videoDB/061/619/video61619/as20121127_doctorwho_pod.mp4" length="36745756" type="video/mp4" />"

tag="url="
parse="<enclosure"
format="mp4"