/bin/sh linked to dash?

I wonder whether amd64 wheezy links /bin/sh to dash instead of bash.

I am getting error "Bad fd number, can't run mopac.h" in a mopac.sh
calculation (mopac compiled fortran, in fact a FOR005 file is
generated, and not deleted by mopac probably because it was running
bad).

I am asking that (and thus if a symlink is needed using bash, as in my
case) because with the same code (and same calculation) I had no such
error with amd64 lenny. I have just copied the whole
molecular-mechanics compiled code (which includes mopac among hundreds
of other codes) from a lenny machine to a wheezy machine. The reason
of the copy is that the molecular-mechanics code can't be compiled
with recent gcc/fortran (its loose fortran is not allowed by recent
compilers) while the wheezy cuda machine is far faster than the old
cpu machine.

thanks
francesco pietra