Generator of passwords

genpass.go

package main

import (
	"fmt"
	"math/rand"
	"os"
	"strconv"
	"strings"
)

var template []string

const DEFAULT_LEN = 16

func init() {
	// printable ASCII symbols range is [32, 127),
	// the start of a range is a space symbol (32),
	// for password generation it may confuse when appears at the end of string,
	// so let's exclude it from a range.
	for i := 33; i < 127; i++ {
		template = append(template, string(rune(i)))
	}
}

func genRandomString(n int) string {
	var b strings.Builder
	for i := 0; i < n; i++ {
		fmt.Fprint(&b, template[rand.Intn(len(template))])
	}
	return b.String()
}

func main() {
	if len(os.Args) < 2 {
		fmt.Println(genRandomString(DEFAULT_LEN))
	} else {
		n, err := strconv.Atoi(os.Args[1])
		if err != nil {
			fmt.Println(err)
			os.Exit(1)
		}
		fmt.Println(genRandomString(n))
	}
}