Thanks. You are right. Examining $? helps to know if the child process executed correctly or not.

Here my sample code:

eval
{
    open my $pipe, "perl --version |";
    my @res = <$pipe>;
    close $pipe;
};

print "Exit Status: " . ($?>>8);
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If I use the not existing command "perl2 --version" then I get the following error message and the exit status 1.

Der Befehl "perl2" ist entweder falsch geschrieben oder
konnte nicht gefunden werden.
Exit Status: 1
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If I use an existing command like "perl --version" then I get the exit status 0 and no error message:

Exit Status: 0
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Problem of course is that I then know the error not directly after the open, but only when the child process exited, that means after the close.