The following conditions are available for performing numerical tests:
<number1> is above <number2>
<number1> is not above <number2>
<number1> is below <number2>
<number1> is not below <number2>
e.g. $message_size is not above 10k
The <number> arguments must expand to strings of digits, optionally followed by one of the letters K or M (upper case or lower case) which cause multiplication by 1024 and 1024x1024 respectively.