I think defined() is a good idea if there's a possibility of $foo being undefined, so as to avoid a warning about an undef being used in a string comparison/regex. Assuming an undefined value counts as a blank, I would write it like this:

if (!defined($foo) or $foo =~ m/^\??$/) {
    # Foo is valid
}

[download]

Thus: "If foo is undefined, or matches an empty string or a single question mark."

But wasn't there something about \n's counting as "^" and/or "$"? Hmmm...

The Secret to Fortune Cookies in One Line
print join("... in bed", `fortune fortunes` =~ m/^(.*)(\.|\?|\!)$/), "\n";

In reply to defined() might be a good idea by BronzeWing
in thread Check on if statement by Anonymous Monk

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