In reply to Kerri.

Thank you, Kerri. Yes, sure you can use any of them (-eq, -ne, -gt, -ge, -lt, -le) - see these Bash scripting binary comparison operators. You also raised an excellent question expanding the scenario to 0 and 1 as acceptable values. It depends, whether warnings are acceptable or not. Ideally, we should strive to eliminate all warnings by proper coding, however sometimes warnings have nothing to do with the quality of our code, for example you can get a warning that your SAS software is expiring soon and you need to update your license.