'perldoc -q space'

Found in perlfaq4
  How do I strip blank space from the beginning/end of a string?
    Although the simplest approach would seem to be

        $string =~ s/^\s*(.*?)\s*$/$1/;

    not only is this unnecessarily slow and destructive, it also fails
+ with
    embedded newlines. It is much faster to do this operation in two s
+teps:

        $string =~ s/^\s+//;
        $string =~ s/\s+$//;

    Or more nicely written as:

        for ($string) {
            s/^\s+//;
            s/\s+$//;
        }

    This idiom takes advantage of the "foreach" loop's aliasing behavi
+or to
    factor out common code. You can do this on several strings at once
+, or
    arrays, or even the values of a hash if you use a slice:

        # trim whitespace in the scalar, the array,
        # and all the values in the hash
        foreach ($scalar, @array, @hash{keys %hash}) {
            s/^\s+//;
            s/\s+$//;
        }
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