open OUT, ">", "./trace.out";

for (0, 1, 2) {
    local $/;
    open my $fdinfo, '<', "/proc/$$/fdinfo/$_";
    my $info = <$fdinfo>;
    print OUT "fdinfo $_:\n$info\n\n";
}

my $line =0;
foreach (@cmdout) {
    $line++;
    my $bytes = print  $line.": ".$_;
    print OUT "$line: bytes: $bytes, err: $! \n";
}
close(OUT);