apache/hadoop · error · UnknownCommandException

Unknown command

Error message

Unknown command

What it means

Error "Unknown command" thrown in apache/hadoop.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FsShell.java:316

   * run
   */
  @Override
  public int run(String[] argv) {
    // initialize FsShell
    init();
    Tracer tracer = new Tracer.Builder("FsShell").
        conf(TraceUtils.wrapHadoopConf(SHELL_HTRACE_PREFIX, getConf())).
        build();
    int exitCode = -1;
    if (argv.length < 1) {
      printUsage(System.err);
    } else {
      String cmd = argv[0];
      Command instance = null;
      try {
        instance = commandFactory.getInstance(cmd);
        if (instance == null) {
          throw new UnknownCommandException();
        }
        TraceScope scope = tracer.newScope(instance.getCommandName());
        if (scope.getSpan() != null) {
          String args = StringUtils.join(" ", argv);
          if (args.length() > 2048) {
            args = args.substring(0, 2048);
          }
          scope.getSpan().addKVAnnotation("args", args);
        }
        try {
          exitCode = instance.run(Arrays.copyOfRange(argv, 1, argv.length));
        } finally {
          scope.close();
        }
      } catch (IllegalArgumentException e) {
        if (e.getMessage() == null) {
          displayError(cmd, "Null exception message");
          e.printStackTrace(System.err);

View on GitHub (pinned to 2add963021)

Solutions

1. Use a valid FsShell command name; see 'hadoop fs -help'.
2. Ensure the command class is registered in the shell's command factory.

When it happens

Trigger: Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FsShell.java:316 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/a67af7eb5a2c1f82. Report an issue: GitHub.