I don't mean what it returns, I mean that returning non-zero trips up Bash into thinking it's a non-successful error code. The fact that doing math can trip up

I don't mean what it returns, I mean that returning non-zero trips up Bash into thinking it's a non-successful error code. The fact that doing math can trip up error detection implies a fundamental design flaw of the system. Which, I mean, we're in Bash, of course it's poorly designed. I didn't know it was quite this bad though.