如果和其他干扰golang中的变量范围

I have following golang code:

        var cmd1 *exec.Cmd
         msg=receive_cmd();
        if strings.Contains(msg, "Log-In") {
             cmd1 := exec.Command("echo", "Please log in")
        }
        else {
        if strings.Contains(msg, "SignUp") {
             cmd1 := exec.Command("echo", "Please SignUp")
          }
        }
       var out bytes.Buffer
       var stderr bytes.Buffer
       cmd1.Stdout = &out
       cmd1.Stderr = &stderr
       err1 := cmd1.Run()
      if err1 != nil {
         fmt.Println(fmt.Sprint(err1) + " ##:## " + stderr.String() + "#####" + out.String())
        return
    }

I expect echo command with "Please log in" if login msg is received and "Please SignUp" if the message is SignUp.

When i am trying above code it says cmd1 declared but not used. how can i remove this error? whats the reason for the error? i have gone though many stack overflow answer on this but nothing is helping.

Go is lexically scoped using blocks. You're using the short variable declaration syntax to declare a new cmd1 variable in each if block. Assign the value to the existing variable with =

var cmd1 *exec.Cmd
msg = receive_cmd()
if strings.Contains(msg, "Log-In") {
    cmd1 = exec.Command("echo", "Please log in")
} else if strings.Contains(msg, "SignUp") {
    cmd1 = exec.Command("echo", "Please SignUp")
}

if strings.Contains(msg, "Log-In") {
    cmd1 = exec.Command("echo", "Please log in")
} else {
    if strings.Contains(msg, "SignUp") {
        cmd1 = exec.Command("echo", "Please SignUp")
    }
}

You need to make sure not to redeclare cmd1 by using = instead of :=, in addition to keeping else on the same line as the preceding }.