Andrew's git / gitweb.git / git-prune-script
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git-prune-scripton commit Add "tag" objects that can be used to sign other objects. (ec4465a)
   1#!/bin/sh
   2fsck-cache --unreachable $(cat .git/HEAD ) | grep unreachable | cut -d' ' -f3 | sed 's:^\(..\):.git/objects/\1/:' | xargs rm