# Appendix A. ASCII Character Set

This appendix presents the set of ASCII characters, along with their equivalent values in decimal, octal, and hexadecimal. The first table shows nonprinting characters; it's useful when you need to represent nonprinting characters in some printed form, such as octal. For example, the `echo` and `tr` commands let you specify characters using octal values of the form \nnn. Also, the `od` command can display nonprinting characters in a variety of forms.

The second table shows printing characters. This table is useful when using the previous commands, but also when specifying a range of characters in a pattern-matching construct.

#### Table A-1. Nonprinting Characters

Decimal | Octal | Hex | Character | Remark
--- | --- | --- | --- | ---
0 | 000 | 00 | CTRL-@ | NUL (Null prompt)
1 | 001 | 01 | CTRL-A | SOH (Start of heading)
2 | 002 | 02 | CTRL-B | STX (Start of text)
3 | 003 | 03 | CTRL-C | ETX (End of text)
4 | 004 | 04 | CTRL-D | EOT (End of transmission)
5 | 005 | 05 | CTRL-E | ENQ (Enquiry)
6 | 006 | 06 | CTRL-F | ACK (Acknowledge)
7 | 007 | 07 | CTRL-G | BEL (Bell)
8 | 010 | 08 | CTRL-H | BS (Backspace)
9 | 011 | 09 | CTRL-I | HT (Horizontal tab)
10 | 012 | 0A | CTRL-J | LF (Linefeed)
11 | 013 | 0B | CTRL-K | VT (Vertical tab)
12 | 014 | 0C | CTRL-L | FF (Formfeed)
13 | 015 | 0D | CTRL-M | CR (Carriage return)
14 | 016 | 0E | CTRL-N | SO (Shift out)
15 | 017 | 0F | CTRL-O | SI (Shift in)
16 | 020 | 10 | CTRL-P | DLE (Data link escape)
17 | 021 | 11 | CTRL-Q | DC1 (XON)
18 | 022 | 12 | CTRL-R | DC2
19 | 023 | 13 | CTRL-S | DC3 (XOFF)
20 | 024 | 14 | CTRL-T | DC4
21 | 025 | 15 | CTRL-U | NAK (Negative acknowledge)
22 | 026 | 16 | CTRL-V | SYN (Synchronous idle)
23 | 027 | 17 | CTRL-W | ETB (End transmission blocks)
24 | 030 | 18 | CTRL-X | CAN (Cancel)
25 | 031 | 19 | CTRL-Y | EM (End of medium)
26 | 032 | 1A | CTRL-Z | SUB (Substitute)
27 | 033 | 1B | CTRL-[ | ESC (Escape)
28 | 034 | 1C | CTRL-\ | FS (File separator)
29 | 035 | 1D | CTRL-] | GS (Group separator)
30 | 036 | 1E | CTRL-^ | RS (Record separator)
31 | 037 | 1F | CTRL-_ | US (Unit separator)
127 | 177 | 7F |  | DEL (Delete or rubout)

#### Table A-2. Printing Characters

Decimal | Octal | Hex | Character | Remark
--- | --- | --- | --- | ---
32 | 040 | 20 |  | Space
33 | 041 | 21 | `!` | Exclamation point
34 | 042 | 22 | `"` | Double quote
35 | 043 | 23 | # | Pound sign
36 | 044 | 24 | $ | Dollar sign
37 | 045 | 25 | % | Percent sign
38 | 046 | 26 | & | Ampersand
39 | 047 | 27 | `'` | Apostrophe
40 | 050 | 28 | ( | Left parenthesis
41 | 051 | 29 | ) | Right parenthesis
42 | 052 | 2A | * | Asterisk
43 | 053 | 2B | + | Plus sign
44 | 054 | 2C | `,` | Comma
45 | 055 | 2D | – | Hyphen
46 | 056 | 2E | `.` | Period
47 | 057 | 2F | / | Slash
48 | 060 | 30 | 0 |
49 | 061 | 31 | 1 |
50 | 062 | 32 | 2 |
51 | 063 | 33 | 3 |
52 | 064 | 34 | 4 |
53 | 065 | 35 | 5 |
54 | 066 | 36 | 6 |
55 | 067 | 37 | 7 |
56 | 070 | 38 | 8 |
57 | 071 | 39 | 9 |
58 | 072 | 3A | `:` | Colon
59 | 073 | 3B | `;` | Semicolon
60 | 074 | 3C | < | Left angle bracket
61 | 075 | 3D | = | Equal sign
62 | 076 | 3E | > | Right angle bracket
63 | 077 | 3F | ? | Question mark
64 | 100 | 40 | @ | At sign
65 | 101 | 41 | A |
66 | 102 | 42 | B |
67 | 103 | 43 | C |
68 | 104 | 44 | D |
69 | 105 | 45 | E |
70 | 106 | 46 | F |
71 | 107 | 47 | G |
72 | 110 | 48 | H |
73 | 111 | 49 | I |
74 | 112 | 4A | J |
75 | 113 | 4B | K |
76 | 114 | 4C | L |
77 | 115 | 4D | M |
78 | 116 | 4E | N |
79 | 117 | 4F | O |
80 | 120 | 50 | P |
81 | 121 | 51 | Q |
82 | 122 | 52 | R |
83 | 123 | 53 | S |
84 | 124 | 54 | T |
85 | 125 | 55 | U |
86 | 126 | 56 | V |
87 | 127 | 57 | W |
88 | 130 | 58 | X |
89 | 131 | 59 | Y |
90 | 132 | 5A | Z |
91 | 133 | 5B | [ | Left square bracket
92 | 134 | 5C | \ | Backslash
93 | 135 | 5D | ] | Right square bracket
94 | 136 | 5E | ^ | Caret
95 | 137 | 5F | _ | Underscore
96 | 140 | 60 | `‘` | Back quote
97 | 141 | 61 | a |
98 | 142 | 62 | b |
99 | 143 | 63 | c |
100 | 144 | 64 | d |
101 | 145 | 65 | e |
102 | 146 | 66 | f |
103 | 147 | 67 | g |
104 | 150 | 68 | h |
105 | 151 | 69 | i |
106 | 152 | 6A | j |
107 | 153 | 6B | k |
108 | 154 | 6C | l |
109 | 155 | 6D | m |
110 | 156 | 6E | n |
111 | 157 | 6F | o |
112 | 160 | 70 | p |
113 | 161 | 71 | q |
114 | 162 | 72 | r |
115 | 163 | 73 | s |
116 | 164 | 74 | t |
117 | 165 | 75 | u |
118 | 166 | 76 | v |
119 | 167 | 77 | w |
120 | 170 | 78 | x |
121 | 171 | 79 | y |
122 | 172 | 7A | z |
123 | 173 | 7B | { | Left curly brace
124 | 174 | 7C | | | Vertical bar
125 | 175 | 7D | } | Right curly brace
126 | 176 | 7E | `~` | Tilde

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