random_generator.go

package main

import (
    "flag"
    "fmt"
    "math/rand"
    "time"
)

var (
    passwordLength int
    useSymbols bool
    letterRunes = []rune("1234567890ABCDEFGHJKLMNPQRSTUVWXYZghjkmnpqrstuvwxy")
    symbolRunes = []rune("!@#$&?")
)

func init() {
    flag.IntVar(&passwordLength, "length", 12, "-len 12, -l 12")
    flag.IntVar(&passwordLength, "l", 12, "")
    flag.BoolVar(&useSymbols, "symbols", false, "use additional symbols: [!@#$&?]")
    flag.BoolVar(&useSymbols, "s", false, "")

    flag.Parse()
    if useSymbols {
        letterRunes = append(letterRunes, symbolRunes...)
    }

    rand.Seed(time.Now().UnixNano())
}

func main() {
    fmt.Println(getRandString(passwordLength))
}

func getRandString(l int) string {
    b := make([]rune, l)
    for i := range b {
        b[i] = letterRunes[rand.Intn(len(letterRunes))]
    }
    return string(b)
}