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

Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: "The first step is to ensure that a Cloudera repository file exists under the /etc/yum.repos.d directory, on the server hc2nn and all of the other Hadoop cluster servers."

A block of code is set as follows:

export AWS_ACCESS_KEY_ID="QQpl8Exxx"
export AWS_SECRET_ACCESS_KEY="0HFzqt4xxx"

./spark-ec2  
    --key-pair=pairname 
    --identity-file=awskey.pem 
    --region=us-west-1 
    --zone=us-west-1a  
    launch cluster1

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

[hadoop@hc2nn ec2]$ pwd

/usr/local/spark/ec2

[hadoop@hc2nn ec2]$ ls
deploy.generic  README  spark-ec2  spark_ec2.py

New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: "Select the User Actions option, and then select Manage Access Keys."