无法正确读取CLI标志

As stated in the title, I'm not able to properly print -e flag valuetest@test.com.

This is my code so far:

package main

import (
    "flag"
    "fmt"
)

func main() {
    var email string
    flag.StringVar(&email, "e", "", "email")
    flag.Parse()
    fmt.Println(email)
}

After running with go run test.go -e=test@test.com I get test@test output.

How do I get "test@test.com"?

Run it in single quotation marks so the shell leave it as it is

go run test.go '-e=test@test.com'