Have you tried something like:

$system = system("cp a b");
if ($system > 0) {
   print("Error occured: $signal\n");
} else {
...do whatever comes next...
}
[download]

Unix returns an exit value when it completes a command so you should be able to assign that value to $signal and test it for its value. Look at the man page for cp for some ideas. Good luck.

MadraghRua
yet another biologist hacking perl....