text: const fs = require('fs');
  
  // console.log(process.argv);
  
  const main = () => {
      try {
          if (process.argv.length < 5) {
              throw new Error('not enough arguments');
          }
  
          const op = process.argv[2];
  
          const input = process.argv[3];
          const output = process.argv[4];
  
          if (op == 'encode') {
              encode(input, output);
          } else if (op == 'decode') {
              decode(input, output);
          } else {
              throw new Error(`Invalid operation ${op}`);
          }
      } catch (error) {
          console.log(`execution failed ${error}`);
          console.log('usage endcode/decode {input_file_name} {output_file_name}');
      }
  }
  
  const encode = (input, output) => {
      console.log('encode', input, output);
      throw new Error('not implemented');
  }
  
  const decode = (input, output) => {
      console.log('decode', input, output);
      throw new Error('not implemented');
  }
  
  main();