  The shape function f(k_+) describes Fermi motion effects in inclusive
semi-leptonic decays such as B -> X_u+e+nu near the end-point of the lepton
spectrum. We compute the leading one-loop corrections to the shape function
f(k_+) in the effective theory with a hard cut-off regularization. The matching
constant onto full QCD is infrared safe, i.e. the leading infrared singularity
represented by the term log^2(k_+) cancels in the difference of integrals. We
compare the hard cut-off result with the result in dimensional regularization,
the latter containing an additional factor of two in the coefficient of the
log^2(k_+) term, and consequently requiring an oversubtraction.
