Liquid nanofilms are ubiquitous in nature and technology, and their
equilibrium and out-of-equilibrium dynamics are key to a multitude of phenomena
and processes. We numerically study the evolution and rupture of viscous
nanometric films, incorporating the effects of surface tension, van der waals
forces, thermal fluctuations and viscous shear. We show that thermal
fluctuations create perturbations that can trigger film rupture, but they do
not significantly affect the growth rate of the perturbations. The film rupture
time can be predicted from a linear stability analysis of the governing thin
film equation, by considering the most unstable wavelength and the thermal
roughness. Furthermore, applying a sufficiently large unidirectional shear can
stabilise large perturbations, creating a finite-amplitude travelling wave
instead of film rupture. In contrast, in three dimensions, unidirectional shear
does not inhibit rupture, as perturbations are not suppressed in the direction
perpendicular to the applied shear. However, if the direction of shear varies
in time, the growth of large perturbations is prevented in all directions, and
rupture can hence be impeded