  We prove that for a 7-dimensional manifold M with cylindrical ends the moduli
space of exponentially asymptotically cylindrical torsion-free G_2 structures
is a smooth manifold (if non-empty), and study some of its local properties. We
also show that the holonomy of the induced metric of an exponentially
asymptotically cylindrical G_2 manifold M is exactly G_2 if and only if its
fundamental group is finite and neither M nor any double cover of M is
homeomorphic to a cylinder.
