use SysCall3;
my $nasty = SysCall3 -> exec( 'bigNastyProgram' );
for my $err ( $nasty -> getinfo( 'STDERR' ) ) {
    # process the error output
    print STDERR $err;
}
for my $out ( $nasty -> getinfo ('STDOUT' ) ) {
    # process the stdout
    print $out;
}
my $code = $nasty -> getinfo( 'EXITCODE' );
# process return code
exit $code; # if wanting to pass control back to the o/s