in reply to Why am I get a core dump when I use ??{}

My first guess is abuse of $1.

Why not just call tr/// to count characters? 

while (<DATA>) {
    print qq("$_" ),
          tr/ // <= 1 ? "has 1 or no spaces\n"
                      : "has more than one space\n";
}

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After Compline,
Zaxo

In Section Seekers of Perl Wisdom