Golang program to parse a command line flag of string type

Program/Source Code:

The source code to parse a command line flag of string type is given below. The given program is compiled and executed on the ubuntu 18.04 operating system successfully.

// Golang program to parse a
// command line flag of string type

package main

import "fmt"
import "flag"

func main() {
	colorPtr := flag.String("color", "red", "a string")

	fmt.Println("Default value of color: ", *colorPtr)
	flag.Parse()

	fmt.Println("Value of color flag: ", *colorPtr)
}

Output:

$ go run hello.go -color=green

Default value of color:  red
Value of color flag:  green

Explanation:

In the above program, we declare the package main. The main package is used to tell the Go language compiler that the package must be compiled and produced the executable file. Here, we imported the fmt, flag packages then we can use a function related to the fmt and flag package.

In the main() function, we passed string type flag from the command line during program execution and then parse command line flag "color" using flag.String(), flag.Parse() functions and printed the default and actual value of the specified flag on the console screen.