loading\\x7f
DEL in hexadecimal \\cC
Control-C
\\x{263a}
Unicode (smiley)
\\N{NAME}
Named character (需要使用use charnames) \%u
Force next character to uppercase \\l
Force next character to lowercase \\U
Force all following characters to uppercase \\L
Force all following characters to lowercase \\Q
Backslash all following nonalphanumeric characters \\E
End \\U, \\L, or \\Q
Perl除了使用单引号和双引号来引，还可以使用q//与qq//的更一般格式，Perl的引用结构如下：
Customary Generic Meaning Interpolates ‘’ q//
Literal String NO
ANDLE FORMAT, LISTprintf FORMAT, LIST(相当于print FILEHANDLE