How Do I Access and Parse Command-Line Arguments in Go?

Accessing Command-Line Arguments in Go

In Go, command-line arguments are available through the os.Args variable. This variable is a slice of strings containing the path to the executable and the arguments passed to it.

Syntax:

import "os"

func main() {
    fmt.Println(len(os.Args), os.Args)
}

Output:

3 [./myprogram arg1 arg2]

The first element of the slice, os.Args[0], is the path to the executable. The remaining elements, os.Args[1:], contain the arguments passed to the program.

Example Usage:

The following Go program reads and prints the command-line arguments passed to it:

package main

import (
    "fmt"
    "os"
)

func main() {
    for i, arg := range os.Args {
        fmt.Printf("%d: %s\n", i, arg)
    }
}

Using the Flag Package

The Go standard library also provides the flag package for parsing command-line flags. Flags can be defined and then used to parse the input arguments.

Syntax:

import "flag"

var myflag bool

func init() {
    flag.BoolVar(&myflag, "myflag", false, "Enable my flag")
}

func main() {
    flag.Parse()
}

By defining a flag named "myflag", the program can be called with the --myflag option to enable it.

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