在vim中显示出特殊字符，设置方法: :set invlist
vim中的特殊字符有：
char digraph hex dec official name ~
^@ NU 0x00 0 NULL (NUL)
^A SH 0x01 1 START OF HEADING (SOH)
^B SX 0x02 2 START OF TEXT (STX)
^C EX 0x03 3 END OF TEXT (ETX)
^D ET 0x04 4 END OF TRANSMISSION (EOT)
^E EQ 0x05 5 ENQUIRY (ENQ)
^F AK 0x06 6 ACKNOWLEDGE (ACK)
^G BL 0x07 7 BELL (BEL)
^H BS 0x08 8 BACKSPACE (BS)
^I HT 0x09 9 CHARACTER TABULATION (HT)
^@ LF 0x0a 10 LINE FEED (LF)
^K VT 0x0b 11 LINE TABULATION (VT)
^L FF 0x0c 12 FORM FEED (FF)
^M CR 0x0d 13 CARRIAGE RETURN (CR)
^N SO 0x0e 14 SHIFT OUT (SO)
^O SI 0x0f 15 SHIFT IN (SI)
^P DL 0x10 16 DATALINK ESCAPE (DLE)
^Q D1 0x11 17 DEVICE CONTROL ONE (DC1)
^R D2 0x12 18 DEVICE CONTROL TWO (DC2)
^S D3 0x13 19 DEVICE CONTROL THREE (DC3)
^T D4 0x14 20 DEVICE CONTROL FOUR (DC4)
^U NK 0x15 21 NEGATIVE ACKNOWLEDGE (NAK)
^V SY 0x16 22 SYNCHRONOUS IDLE (SYN)
^W EB 0x17 23 END OF TRANSMISSION BLOCK (ETB)
^X CN 0x18 24 CANCEL (CAN)
^Y EM 0x19 25 END OF MEDIUM (EM)
^Z SB 0x1a 26 SUBSTITUTE (SUB)
^[ EC 0x1b 27 ESCAPE (ESC)
^ FS 0x1c 28 FILE SEPARATOR (IS4)
^] GS 0x1d 29 GROUP SEPARATOR (IS3)
^^ RS 0x1e 30 RECORD SEPARATOR (IS2)
^_ US 0x1f 31 UNIT SEPARATOR (IS1)
SP 0x20 32 SPACE
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