apache/hadoop · error · IOException

missing destination argument

Error message

missing destination argument

What it means

IOException('missing destination argument') thrown by AppendToFile.processOptions (CopyCommands.java:382) when fewer than 2 arguments remain after option parsing. appendToFile requires at least one source (local file or '-') AND one destination, so args.size() < 2 means the destination (or both arguments) was omitted.

Source

Thrown at hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/shell/CopyCommands.java:382

          items.add(new PathData(new URI(arg), getConf()));
        } catch (URISyntaxException e) {
          if (Path.WINDOWS) {
            // Unlike URI, PathData knows how to parse Windows drive-letter paths.
            items.add(new PathData(arg, getConf()));
          } else {
            throw new IOException("Unexpected URISyntaxException: " + e.toString());
          }
        }
      }
      return items;
    }

    @Override
    protected void processOptions(LinkedList<String> args)
        throws IOException {

      if (args.size() < 2) {
        throw new IOException("missing destination argument");
      }

      CommandFormat cf = new CommandFormat(2, Integer.MAX_VALUE, "n");
      cf.parse(args);
      appendToNewBlock = cf.getOpt("n");
      getRemoteDestination(args);
      super.processOptions(args);
    }

    @Override
    protected void processArguments(LinkedList<PathData> args)
        throws IOException {

      if (!dst.exists) {
        dst.fs.create(dst.path, false).close();
      }

      InputStream is = null;

View on GitHub (pinned to 2add963021)

Solutions

1. Supply both arguments: 'hadoop fs -appendToFile local.txt /hdfs/log.txt'
2. If the destination comes from a variable, guard the script: [ -n "$DEST" ] || { echo 'DEST unset'; exit 1; }
3. Check the exact command line the failing job/launcher executes (print it before running)

Example fix

# before
hadoop fs -appendToFile $LOCAL_FILE $DEST   # $DEST is empty -> missing destination argument

# after
[ -n "$DEST" ] || { echo "DEST is empty" >&2; exit 1; }
hadoop fs -appendToFile "$LOCAL_FILE" "$DEST"

if (args.size() < 2) {
  throw new IOException("missing destination argument");
}

try {
  // invoke appendToFile
} catch (IOException e) {
  if (e.getMessage().contains("missing destination argument")) {
    // fix the argument list (source + destination required) and retry
  }
}

When it happens

Trigger: 'hadoop fs -appendToFile local.txt' (no HDFS destination); calling with only flags; a script where $DEST expanded to empty so the destination argument vanished.

Common situations: Unset/empty environment variables in cron or CI scripts; shell quoting mistakes that swallow the last argument; commands copy/pasted without the trailing destination token.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• stdin (-) must be the sole input argument when present
• Illegal option {}
• Not enough arguments: expected {} but got {}
• Too many arguments: expected {} but got {}
• Target path not specified. <target path> <src path> <src pat

AI-assisted analysis of apache/hadoop@2add963021 (2026-08-22). Data as JSON: /api/errors/f446fc33e0b81b0d. Report an issue: GitHub.