How to use default values for command-line flags in Go?

In Go, you can use the flag package to parse command-line arguments and provide default values for the flags. Here's how you can use default values for command-line flags in Go:

Import the flag package:

import "flag"

Define a variable for each command-line flag and assign a default value using the flag package. For example:

var someFlag = flag.String("flagname", "defaultvalue", "description")

In the above example:

flagname is the name of the flag.
defaultvalue is the default value for the flag.
description is an optional description for the flag.

Call the flag.Parse() function to parse the command-line arguments and handle the default values. For example:

func main() {
    flag.Parse()

    // Rest of your code
}

Access the flag value in your program using the corresponding variable. For example:

func main() {
    flag.Parse()

    // Access the flag value
    fmt.Println("Flag Value:", *someFlag)
}

That's it! Now, when you run your Go program without providing a value for a flag, it will use the default value defined in step 2.

Here's a complete example that demonstrates the usage of default values for command-line flags in Go:

package main

import (
    "flag"
    "fmt"
)

var someFlag = flag.String("flagname", "defaultvalue", "description")

func main() {
    flag.Parse()

    fmt.Println("Flag Value:", *someFlag)
}

When you run this program without providing a value for the flagname flag, it will use the default value of defaultvalue.