root@maggie:/etc/apt# apt-get update
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[snip]
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Reading package lists... Done
W: Duplicate sources.list entry http://www.deb-multimedia.org/ wheezy/non-free amd64 Packages (/var/lib/apt/lists/www.deb-multimedia.org_dists_wheezy_non-free_binary-amd64_Packages)
W: You may want to run apt-get update to correct these problems
root@maggie:/etc/apt# grep -c multimedia sources.list
1
root@maggie:/etc/apt#