FAQ 4.37: What's wrong with always quoting "$vars"?

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4.37: What's wrong with always quoting "$vars"?

    The problem is that those double-quotes force stringification-- coercing
    numbers and references into strings--even when you don't want them to be
    strings. Think of it this way: double-quote expansion is used to produce
    new strings. If you already have a string, why do you need more?

    If you get used to writing odd things like these:

        print "$var";       # BAD
        $new = "$old";      # BAD
        somefunc("$var");   # BAD

    You'll be in trouble. Those should (in 99.8% of the cases) be the
    simpler and more direct:

        print $var;
        $new = $old;

    Otherwise, besides slowing you down, you're going to break code when the
    thing in the scalar is actually neither a string nor a number, but a

        sub func {
            my $aref = shift;
            my $oref = "$aref";  # WRONG

    You can also get into subtle problems on those few operations in Perl
    that actually do care about the difference between a string and a
    number, such as the magical "++" autoincrement operator or the syscall()

    Stringification also destroys arrays.

        @lines = `command`;
        print "@lines";             # WRONG - extra blanks
        print @lines;               # right


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