Read Command Output as String

The title is pretty self explanatory. I'm sure there's a way to do this, but I haven't seen any questions of this variety answered. There's several situations where this would be useful- for me personally, the ability to read array-type metadata for stuff like villager trades would be helpful, (I think there may be a plugin for this?) Along with more mundane use cases like locating structures/biomes, reading entity attributes, etc.