@Override
  public int execute() throws HiveException, IOException {
    ConfVars conf = HiveConf.getConfVars(desc.getConfName());
    if (conf == null) {
      throw new HiveException("invalid configuration name " + desc.getConfName());
    }
    String description = conf.getDescription();
    String defaultValue = conf.getDefaultValue();

    try (DataOutputStream output = ShowUtils.getOutputStream(desc.getResFile(), context)) {
      if (defaultValue != null) {
        output.write(defaultValue.getBytes(StandardCharsets.UTF_8));
      }
      output.write(Utilities.tabCode);
      output.write(conf.typeString().getBytes(StandardCharsets.UTF_8));
      output.write(Utilities.tabCode);
      if (description != null) {
        output.write(description.replaceAll(" *\n *", " ").getBytes(StandardCharsets.UTF_8));
      }
      output.write(Utilities.newLineCode);
    }

    return 0;
  }
Operation process of showing some configuration.
ql/src/java/org/apache/hadoop/hive/ql/ddl/misc/conf/ShowConfOperation.java