I would be tempted to handle it this way:

my $pid = fork();
if ($pid == 0) {
    # child process
    my $exit = system("whatever command you want");
    if ($exit != 0) {
        # handle error
    }
    exit;
}
# rest of the program that isn't waiting on the 'system'
.
.
.
[download]

This way you can handle any errors that might result from the system command, and not have to wait for it to finish.

If later in your code you need to make sure that the system has finished before you go on, you can use waitpid($pid,0) to have this process pause until the other has exited.

/\/\averick