How Do I Retrieve and Use Command-Line Arguments in Go?

Retrieving Command-Line Arguments in Go Programs

In Go, command-line arguments are not directly passed as parameters to the main function. To access them, the os.Args variable provides a slice of strings representing the arguments passed to the program.

Accessing Arguments with os.Args

The os.Args variable is available within the main function and holds the following information:

• os.Args[0]: Program name
• os.Args[1:]: Command-line arguments

Example:

package main

import (
    "fmt"
    "os"
)

func main() {
    fmt.Println("Program name:", os.Args[0])
    fmt.Println("Arguments:", os.Args[1:])
}

This program prints the name of the program and the command-line arguments passed to it.

Using the flag Package

Go also provides the flag package, which simplifies command-line argument parsing. The flag package allows you to define and parse flags, which are named parameters that can be set when the program is invoked.

Example:

package main

import (
    "flag"
    "fmt"
)

var name string

func init() {
    flag.StringVar(&name, "name", "Default name", "Set the program's name")
}

func main() {
    flag.Parse()
    fmt.Println("Hello", name)
}

In this example, the -name flag can be used to specify a name. The flag is parsed and assigned to the name variable in the init function.

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