--- chop
--- chop!

    ƥѿ $_ ǸʸΤˤ
    ޤ(ü"\r\n"Ǥ2ʸޤ)
    chop! ʸ󤽤ΤΤѹη̤֤ޤ
    ʸ󤬤ʤ nil ֤ޤ

    ܺ٤ String#chop [String/chop] 򻲾ȤƤ
    $_.chop ȴؿ chop Ǥϰʲǰ㤤ޤ

    * chop  $_ ͤ򥳥ԡơԡ򹹿
      $_ ((**))ޤ

