improve performance with wc -l instead of awk

loading and running awk is more time consuming than wc:

time sed -e '/^$/d' -e '/^#/d' < malhosts.txt | awk 'END { print NR }'
2446
sed -e '/^$/d' -e '/^#/d' < malhosts.txt  0,00s user 0,00s system 51% cpu 0,008 total
awk 'END { print NR }'  0,00s user 0,00s system 55% cpu 0,007 total

time sed -e '/^$/d' -e '/^#/d' < malhosts.txt | wc -l
2446
sed -e '/^$/d' -e '/^#/d' < malhosts.txt  0,00s user 0,00s system 55% cpu 0,007 total
wc -l  0,00s user 0,00s system 0% cpu 0,006 total
Merge pull request #5 from stasic/patch-2

improve performance by using wc -l instead of awk