PERL Regexp Quote-Like Operators

Regexp ใน perl มีตัว Operators ดังนี้

qr/STRING/msixpodual

ความหมายก็คือ

    m Treat string as multiple lines.

    s Treat string as single line. (Make . match a newline)

    i Do case-insensitive pattern matching.

    x Use extended regular expressions.

    p When matching preserve a copy of the matched string so
        that ${^PREMATCH}, ${^MATCH}, ${^POSTMATCH} will be defined.

    o Compile pattern only once.

    l Use the locale

    u Use Unicode rules

    a Use ASCII for \d, \s, \w; specifying two a's further restricts

    /i matching so that no ASCII character will match a non-ASCII
        one

    d Use Unicode or native charset, as in 5.12 and earlier

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ref : http://perldoc.perl.org/perlop.html#Regexp-Quote-Like-Operators