locale - Perl pragma to use and avoid 
POSIX locales for built-in operations
    @x = sort @y;       # ASCII sorting order
    {
        use locale;
        @x = sort @y;   # Locale-defined sorting order
    }
    @x = sort @y;       # ASCII sorting order again
This pragma tells the compiler to enable (or disable) the use of 
POSIX locales for built-in operations 
(LC_CTYPE for regular expressions, and 
LC_COLLATE for string comparison). Each ``use locale'' or ``no locale'' affects statements to the end of the enclosing 
BLOCK.