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: "Click on the start button and search for settings option."

A block of code is set as follows:

var http = require("http") http.createServer(function (request, response) {
// Send the HTTP header
// HTTP Status: 200 : OK
// Content Type: text/plain
response.writeHead(200, {'Content-Type': 'text/plain'})
// Send the response body as "Hello World" response.end('Hello World\n')
}).listen(3000)

// Console will print the message console.log('Server running')

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

$ aws ec2 describe-instance-status --instance-ids i-057e8deb1a4c3f35d --output text| grep -i SystemStatus

SYSTEMSTATUS ok

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

$ aws ec2 authorize-security-group-ingress \
   --group-name HelloWorld \
   --protocol tcp \
   --port 3000 \
   --cidr 0.0.0.0/0

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: "In this menu, find the feature called Windows Subsystem for Linux (Beta)."