perl5.md

Letter Casing in Perl 5

Letter casing functions are available in the core language and have Unicode semantics for character strings but ASCII semantics for byte strings.

$lowercase = lc $str;
$uppercase = uc $str;
$titlecase = ucfirst $str;

use v5.16;
$casefold = fc $str;

The fc function was added in Perl 5.16 and requires use v5.16 or use feature 'fc'. The CPAN module Unicode::CaseFold provides the fc function for Perl 5.8.1 or greater.

use Unicode::CaseFold;
$casefold = fc $str;