assertEquals("test1 \" test2", list.get(1));

        cmd = "test.sh $INPUT_FILE";
        params.clear();
        list = extractor.parseCommand(cmd, params);
        assertEquals(2, list.size());
        assertEquals("test.sh", list.get(0));
        assertEquals("$INPUT_FILE", list.get(1));

        cmd = "test.sh $INPUT_FILE $OUTPUT_FILE";
        params.clear();
        list = extractor.parseCommand(cmd, params);

  private void verifyTableSize(int inputSize, int setSize, int tableSize) {
    Builder<Integer> builder = ImmutableSet.builder();
    for (int i = 0; i < inputSize; i++) {
      builder.add(i % setSize);
    }
    ImmutableSet<Integer> set = builder.build();
    assertTrue(set instanceof RegularImmutableSet);
    assertEquals(
        "Input size " + inputSize + " and set size " + setSize,
        tableSize,

        if (StringUtil.isBlank(command)) {
            throw new CrawlerSystemException("command is empty.");
        }

        final Map<String, String> params = new HashMap<>();
        params.put("$INPUT_FILE", inputFile.getAbsolutePath());
        params.put("$OUTPUT_FILE", outputFile.getAbsolutePath());

        final List<String> cmdList = parseCommand(command, params);
        if (logger.isInfoEnabled()) {