In this book, you will find a number of styles of text that distinguish between different kinds of information. Here are some examples of these styles, and an explanation of their meaning.

Code words in text are shown as follows: "From this point onward, we shall call the unpacked Hadoop directory HADOOP_HOME."

A block of code is set as follows:

public void map(Object key, Text value, Context context)   
  throws IOException, InterruptedException
  {
    StringTokenizer itr = new StringTokenizer(value.toString());
    while (itr.hasMoreTokens())
    {
      word.set(itr.nextToken());
      context.write(word, new IntWritable(1));
     }
  }

Any command-line input or output is written as follows:

>tar -zxvf hadoop-1.x.x.tar.gz

New terms and important words are shown in bold. Words that you see on the screen, in menus or dialog boxes for example, appear in the text like this: "Create a S3 bucket to upload the input data by clicking on Create Bucket".