Bash one-liner that summs integers divisable by 3

sum.sh

#it's important to have space after last integer
echo "1 2 3 4 5 " | tee a | sed 's/\s/\/3\n/g' | bc -l | sed 's/00//g' | sed 's/.$//g' | nl | grep -v '\.' | awk '{print $1}' > b; export A=$(cat a | sed 's/\s/\n/g'); export B=$(cat b); for i in $B; do echo -e "$A" | sed "${i}q;d" ; done | tr '\n' ' ' | rev | cut -c 2- | rev | sed 's/\s/+/g' | bc