Command-Line Arguments #

// [_Command-line arguments_](https://en.wikipedia.org/wiki/Command-line_interface#Arguments)
// are a common way to parameterize execution of programs.
// For example, `go run hello.go` uses `run` and
// `hello.go` arguments to the `go` program.

package main

import (
	"fmt"
	"os"
)

func main() {

	// `os.Args` provides access to raw command-line
	// arguments. Note that the first value in this slice
	// is the path to the program, and `os.Args[1:]`
	// holds the arguments to the program.
	argsWithProg := os.Args
	argsWithoutProg := os.Args[1:]

	// You can get individual args with normal indexing.
	arg := os.Args[3]

	fmt.Println(argsWithProg)
	fmt.Println(argsWithoutProg)
	fmt.Println(arg)
}

# To experiment with command-line arguments it's best to
# build a binary with `go build` first.
$ go build command-line-arguments.go
$ ./command-line-arguments a b c d
[./command-line-arguments a b c d]
[a b c d]
c

# Next we'll look at more advanced command-line processing
# with flags.