deduplicate () {
        packages="$1"
        outdir="/tmp/net-retriever-$$-deduplicate"

        mkdir -p "$outdir"

        while [ -s "$packages" ]; do
                entry="$(sed '/^$/q' "$packages")"
                package="$(echo "$entry" | sed -n 's/Package:[[:space:]][[:space:]]*//pI' | head -n 1)"
                case $package in
                    ''|*/*)
                        continue
                        ;;
                    *)
                        if [ -f "$outdir/$package" ]; then
                                newver="$(echo "$entry" | sed -n 's/Version:[[:space:]][[:space:]]*//pI' | head -n 1)"
                                [ "$newver" ] || continue
                                oldver="$(sed -n 's/Version:[[:space:]][[:space:]]*//pI' "$outdir/$package" | head -n 1)"
                                if /usr/lib/net-retriever/vergt "$newver" "$oldver"; then
                                        echo "$entry" > "$outdir/$package"
                                        echo >> "$outdir/$package"
                                fi
                        else
                                echo "$entry" > "$outdir/$package"
                                echo >> "$outdir/$package"
                        fi
                        ;;
                esac
                sed -n '/^$/,$p' "$packages" | tail -n +2 > "$packages.new"
                mv "$packages.new" "$packages"
        done

        cat "$outdir"/* > "$packages.new"
        mv "$packages.new" "$packages"
        rm -rf "$outdir"
}