apache/hadoop · error · TooManyArgumentsException

Too many arguments: expected

Error message

Too many arguments: expected {} but got {}

What it means

Thrown by CommandFormat.parse() when more positional arguments remain after option stripping than the command's declared maximum (maxPar). TooManyArgumentsException extends IllegalArgumentException and reports 'Too many arguments: expected <max> but got <n>'. Only commands constructed with a finite maxPar (e.g. 'test' with maxPar=1) can raise it; commands declared with Integer.MAX_VALUE never do.

Solutions

1. Invoke the command once per path (loop) instead of passing all paths at once to single-path commands like test
2. Quote or pre-validate globs so they expand to the expected number of arguments before the call
3. Re-read 'hdfs dfs -help <command>' to see the accepted argument shape

Example fix

# before
hdfs dfs -test -e /data/a /data/b
# after
hdfs dfs -test -e /data/a && hdfs dfs -test -e /data/b

// single-path commands: assert exactly one positional before running
String[] positional = Arrays.stream(argv).filter(a -> !a.startsWith("-")).toArray(String[]::new);
if (positional.length > 1) {
  throw new IllegalArgumentException("command takes exactly one path, got " + positional.length);
}

try {
  cf.parse(args);
} catch (CommandFormat.TooManyArgumentsException e) {
  // split the workload and run the command once per path
  for (String p : extraPaths) runCommand(singlePathCmd(p));
}

When it happens

Trigger: 'hdfs dfs -test -e /a /b' (test accepts at most one path), passing multiple paths to any single-path command, or a shell glob expanding ('*.csv' to many files) into a command with maxPar=1.

Common situations: Unquoted globs expanding unexpectedly in scripts; users assuming 'test' accepts multiple paths like 'ls'; wrapping loops that feed an array where a single path is expected; misreading an option as a value so a stray token lands in the positional list.

Related errors

• Illegal option
• Not enough arguments: expected
• Target path not specified.
• The number of source paths is less than 2.
• No attribute for

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/2f5d19d305ef6562. Report an issue: GitHub.

Appendix: source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/CommandFormat.java:138

          args.remove(pos);
        } else {
          arg = "";
        }
        if (!arg.startsWith("-") || arg.equals("-")) {
          optionsWithValue.put(opt, arg);
        }
      } else if (ignoreUnknownOpts) {
        pos++;
      } else {
        throw new UnknownOptionException(arg);
      }
    }
    int psize = args.size();
    if (psize < minPar) {
      throw new NotEnoughArgumentsException(minPar, psize);
    }
    if (psize > maxPar) {
      throw new TooManyArgumentsException(maxPar, psize);
    }
  }
  
  /** Return if the option is set or not
   * 
   * @param option String representation of an option
   * @return true is the option is set; false otherwise
   */
  public boolean getOpt(String option) {
    return options.containsKey(option) ? options.get(option) : false;
  }

  /**
   * get the option's value
   *
   * @param option option name
   * @return option value
   * if option exists, but no value assigned, return ""

View on GitHub (pinned to 2add963021)