Oh, blessed are those who never had to deal with the assumption that every shell is bash despite using /bin/sh in shebangs of their scripts, or with the assumpt

Oh, blessed are those who never had to deal with the assumption that every shell is bash despite using /bin/sh in shebangs of their scripts, or with the assumption that all core utilities (like find or grep) are of the GNU flavor. Ignorant they are, yet their ignorance is a bliss.