  Precise knowledge of hadron production rates in the generation of neutrino
beams is necessary for accelerator-based neutrino experiments to achieve their
physics goals. NA61/SHINE, a large-acceptance hadron spectrometer, has recorded
hadron+nucleus interactions relevant to ongoing and future long-baseline
neutrino experiments at Fermi National Accelerator Laboratory. This paper
presents three analyses of interactions of 60 GeV/$c$ $\pi^+$ with thin, fixed
carbon and beryllium targets. Integrated production and inelastic cross
sections were measured for both of these reactions. In an analysis of strange,
neutral hadron production, differential production multiplicities of $K^0_{S}$,
$\Lambda$ and anti-$\Lambda$ were measured. Lastly, in an analysis of charged
hadron production, differential production multiplicities of $\pi^+$, $\pi^-$,
$K^+$, $K^-$ and protons were measured. These measurements will enable
long-baseline neutrino experiments to better constrain predictions of their
neutrino flux in order to achieve better precision on their neutrino cross
section and oscillation measurements.
