21. ASCII Character Set

This section presents the set of ASCII characters, along with their equivalent values in decimal, octal, and hexadecimal. The first table shows nonprinting characters. This table would be 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 be used to display nonprinting characters in a variety of forms.

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

Table 21.1: 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	NP (New page) or 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 (X-ON)
18	022	12	CTRL-R	DC2
19	023	13	CTRL-S	DC3 (X-OFF)
20	024	14	CTRL-T	DC4
21	025	15	CTRL-U	NAK (No 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 21.2: Printing Characters

Decimal	Octal	Hex	Character	Remark
32	040	20		Space
33	041	21	!	Exclamation Point
34	042	22	"	Double quote
35	043	23	#	Sharp 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 (Virgule)
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