In a pure unix environment, is File::Copy::copy($a,$b)
preferred to system('cp',$a,$b)
Presumably, the system call has some process creation overhead, yet I think that system has higher readability.
I think in mixed environments, the case for File::Copy is obvious. There may also be a security reason to avoid calls to system in shared-user environments; also if search path management is poor (e.g., someone sets up a bad cron environment) then File::Copy can be necessitated. I am working in a secure environment where path management should be second nature.