How does reduction of nitriles produce primary amines?

Primary amines can be produced through the catalytic addition of hydrogen to nitriles ($R\equiv CN$). This process involves the reduction of the nitrile group, which effectively converts the carbon-nitrogen triple bond into a single bond, resulting in the formation of a primary amine ($RC{H}_{2}N{H}_2$).1

This method is utilized industrially for the production of specific amines, such as hexamethylenediamine, which is a key component in the manufacture of nylon-6,6.1