Bash trap: Unrecognized signal specification handling divergence between 4.x and 5.x series
Compatibility boundary The trap builtin accepts both signal names and numbers, yet POSIX leaves the treatment of unrecognized specifications implementation-defined. Bash 4.x and 5.x series differ in whether an unknown signal name causes a fatal error, a silent no-op, or a deferred failure at signal delivery time. This affects portable scripts that dynamicall
bash