Practical Go

CHAPTER 1Writing Command-Line Applications

In this chapter, you will learn about the building blocks of writing command-line applications. You will use standard library packages to construct command-line interfaces, accept user input, and learn techniques to test your applications. Let's get started!

Your First Application

All command-line applications essentially perform the following steps:

• Accept user input
• Perform some validation
• Use the input to perform some custom task
• Present the result to the user; that is, a success or a failure

In a command-line application, an input can be specified by the user in several ways. Two common ways are as arguments when executing the program and interactively by typing it in. First you will implement a greeter command-line application that will ask the user to specify their name and the number of times they want to be greeted. The name will be input by the user when asked, and the number of times will be specified as an argument when executing the application. The program will then display a custom message the specified number of times. Once you have written the complete application, a sample execution will appear as follows:

$ ./application 6
Your name please? Press the Enter key when done.
Joe Cool
Nice to meet you Joe Cool
Nice to meet you Joe Cool
Nice to meet you Joe Cool
Nice to meet you Joe Cool
Nice to meet you Joe Cool
Nice to meet you Joe Cool

First, let's look at the function asking a user to input their name:

func getName(r ...