#!/usr/bin/env bash

if ! username=$(osascript 2> /dev/null <<-EOF
tell application "System Events"
  activate
  return text returned of (display dialog "Enter your name" with title ¬
    "Question" default answer "" buttons {"Cancel", "Rename"} default button "Rename")
end tell
EOF
); then
  exit 1
fi

# Continue to do something with $username...
echo "$username"