/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/lib/index.js:79
    throw new Error(['Solidity compiler not found. Please, add solc to path or', 'define environment variable SOLC_PATH.'].join(' '));
    ^

Error: Solidity compiler not found. Please, add solc to path or define environment variable SOLC_PATH.
    at getSolidityCompilerPath (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/lib/index.js:79:11)
    at exports.default (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/lib/index.js:14:30)
    at Command.program.version.arguments.option.action (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/bin/solidity-docgen:32:5)
    at Command.listener (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/node_modules/commander/index.js:315:8)
    at emitOne (events.js:116:13)
    at Command.emit (events.js:211:7)
    at Command.parseArgs (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/node_modules/commander/index.js:656:12)
    at Command.parse (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/node_modules/commander/index.js:474:21)
    at Object.<anonymous> (/home/dog/.nvm/versions/node/v8.12.0/lib/node_modules/solidity-docgen/bin/solidity-docgen:44:9)
    at Module._compile (module.js:653:30)