Note that the feature unicode_strings was introduced in 5.12, but to make \s match \xA0 on a non-utf-8 strings, you need 5.14: 
$ perl-5.14.2 -wE '$_ = chr 0xA0; say /\s/ || 0'
1
$ perl-5.12.2 -wE '$_ = chr 0xA0; say /\s/ || 0'
0

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The -E enables "use feature 'unicode_strings'".

In reply to Re^2: Can I change \s? by JavaFan
in thread Can I change \s? by pileofrogs

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