UNIX for Dummies Questions & Answers

 find . -type f -name "*.conf" -ls | awk '{sum+=$7}END{print sum}'

$ du -sh *.pdf
604K    ch1-Introduction-2.pdf
100K    dist-03-4.pdf

$ du -sh *.pdf|awk '{sum+=$1}END{print sum}'
704

size_tot=0
find /etc/ -type f -name \*\.conf -exec ls -ald {} \;| \
        awk '{print $5}'|while read size
do
        size_tot=$(( ${size_tot} + ${size} ))
done
echo "Total size (bytes) : ${size_tot}"