The hydrolysis of nitriles RCN proceeds in the distinct steps under acid or base treatment to first give carboxamides  and then carboxylic acids RCOOH. The hydrolysis of nitriles to carboxylic acids is efficient.  In acid or base, the balanced equations are as follows:
Strictly speaking, these reactions are mediated (as opposed to catalyzed) by acid or base, since one equivalent of the acid or base is consumed to form the ammonium or carboxylate salt, respectively.
Kinetic studies show that the second-order rate constant for hydroxide-ion catalyzed hydrolysis of acetonitrile to acetamide is 1.6 M s, which is slower than the hydrolysis of the amide to the carboxylate (7.4 M s). Thus, the base hydrolysis route will afford the carboxylate (or the amide contaminated with the carboxylate). On the other hand, the acid catalyzed reactions requires a careful control of the temperature and of the ratio of reagents in order to avoid the formation of polymers, which is promoted by the exothermic character of the hydrolysis. The classical procedure to convert a nitrile to the corresponding primary amide calls for adding the nitrile to cold concentrated sulfuric acid. The further conversion to the carboxylic acid is disfavored by the low temperature and low concentration of water.
Two families of enzymes catalyze the hydrolysis of nitriles.  Nitrilases hydrolyze nitriles to carboxylic acids:
Nitrile hydratases are metalloenzymes that hydrolyze nitriles to amides.  
These enzymes are used commercially to produce acrylamide.
The "anhydrous hydration" of nitriles to amides has been demonstrated using an oxime as water source: