I sed it

echo "Not so easy to understand? Execute it." | sed -e's/[N,e,s,?]//g' -e's/o/H/' -e's/t/a/' -e's/ /p/g' -e's/[o]//g' -e's/ayp/y /' -e's/pun/irt/g' -e's/t/B/' -e's/drt/hda/' -e's/and/y, /' -e's/pExcutp/Am/'