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Conventions used

There are a number of text conventions used throughout this book.

CodeInText: Indicates code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles. Here is an example: "Mount the downloaded WebStorm-10*.dmg disk image file as another disk in your system."

A block of code is set as follows:

export HADOOP_CONF_DIR="${HADOOP_CONF_DIR:-$YARN_HOME/etc/hadoop}"
export HADOOP_COMMON_HOME="${HADOOP_COMMON_HOME:-$YARN_HOME}"
export HADOOP_HDFS_HOME="${HADOOP_HDFS_HOME:-$YARN_HOME}"

When we wish to draw your attention to a particular part of a code block, the relevant lines or items are set in bold:

$ hadoop fs -cat /tmp/output-7/part*
 NewDelhi, 440
 Kolkata, 390
 Bangalore, 270

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

useradd hadoop
passwd hadoop1

Bold: Indicates a new term, an important word, or words that you see onscreen. For example, words in menus or dialog boxes appear in the text like this. Here is an example: "Select System info from the Administration panel."

Warnings or important notes appear like this.

Tips and tricks appear like this.