That did not solve my problem. I may not have explained it correctly so I will try again. The script is to send a reminder to me using the at command. If I am online, then it will write to me. If I am offline, then it will email me. If I am online, the script will "interrupt me" with the reminder but it also sends a mail message with the aforementioned, "stty: :Inappropriate ioctl for device". If I am offline, the script mails me two messages. The original reminder and the "stty: :Inappropriate ioctl for device" message.
When I tried the above code suggested by Corona688, I got no message and received a mail message, "Ambiguous output redirect." Therefor I am stuck.