in reply to Replacing whitespaces with a regex

Just do
$words =~ s/\s\s+$/ /;

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whithout any if. If there is multiple whitespace, it will be replaced, if not, nothing happens.
لսႽ† ᥲᥒ⚪⟊Ⴙᘓᖇ Ꮅᘓᖇ⎱ Ⴙᥲ𝇋ƙᘓᖇ

In Section Seekers of Perl Wisdom