[apple/shell_cmds.git] / printf / printf.1

.\"	$NetBSD: printf.1,v 1.10 1998/08/22 14:54:48 garbled Exp $
.\"
.\" Copyright (c) 1989, 1990, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" the Institute of Electrical and Electronics Engineers, Inc.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"	from: @(#)printf.1	8.1 (Berkeley) 6/6/93
.\"
.Dd November 5, 1993
.Dt PRINTF 1
.Os
.Sh NAME
.Nm printf
.Nd formatted output
.Sh SYNOPSIS
.Nm
.Ar format
.Op Ar arguments  ...
.Sh DESCRIPTION
.Nm
formats and prints its arguments, after the first, under control
of the
.Ar format  .
The
.Ar format
is a character string which contains three types of objects: plain characters,
which are simply copied to standard output, character escape sequences which
are converted and copied to the standard output, and format specifications,
each of which causes printing of the next successive
.Ar argument  .
.Pp
The
.Ar arguments
after the first are treated as strings if the corresponding format is
either
.Cm b ,
.Cm c
or
.Cm s ;
otherwise it is evaluated as a C constant, with the following extensions:
.Pp
.Bl -bullet -offset indent -compact
.It
A leading plus or minus sign is allowed.
.It
If the leading character is a single or double quote, the value is the 
.Tn ASCII
code of the next character.
.El
.Pp
The format string is reused as often as necessary to satisfy the
.Ar arguments  .
Any extra format specifications are evaluated with zero or the null
string.
.Pp
Character escape sequences are in backslash notation as defined in 
.St -ansiC .
The characters and their meanings
are as follows:
.Bl -tag -width Ds -offset indent
.It Cm \ee
Write an <escape> character.
.It Cm \ea
Write a <bell> character.
.It Cm \eb
Write a <backspace> character.
.It Cm \ef
Write a <form-feed> character.
.It Cm \en
Write a <new-line> character.
.It Cm \er
Write a <carriage return> character.
.It Cm \et
Write a <tab> character.
.It Cm \ev
Write a <vertical tab> character.
.It Cm \e\'
Write a <single quote> character.
.It Cm \e\e
Write a backslash character.
.It Cm \e Ns Ar num 
Write an 8-bit character whose
.Tn ASCII
value is the 1-, 2-, or 3-digit
octal number
.Ar num .
.El
.Pp
Each format specification is introduced by the percent character
(``%'').
The remainder of the format specification includes,
in the following order:
.Bl -tag -width Ds
.It "Zero or more of the following flags:"
.Bl -tag -width Ds
.It Cm #
A `#' character
specifying that the value should be printed in an ``alternative form''.
For
.Cm c  ,
.Cm d ,
and
.Cm s  ,
formats, this option has no effect.  For the
.Cm o
formats the precision of the number is increased to force the first
character of the output string to a zero.  For the
.Cm x
.Pq Cm X
format, a non-zero result has the string
.Li 0x
.Pq Li 0X
prepended to it.  For
.Cm e  ,
.Cm E ,
.Cm f  ,
.Cm g ,
and
.Cm G  ,
formats, the result will always contain a decimal point, even if no
digits follow the point (normally, a decimal point only appears in the
results of those formats if a digit follows the decimal point).  For
.Cm g
and
.Cm G
formats, trailing zeros are not removed from the result as they
would otherwise be;
.It Cm \&\-
A minus sign `\-' which specifies
.Em left adjustment
of the output in the indicated field;
.It Cm \&+
A `+' character specifying that there should always be
a sign placed before the number when using signed formats.
.It Sq \&\ \&
A space specifying that a blank should be left before a positive number
for a signed format.  A `+' overrides a space if both are used;
.It Cm \&0
A zero `0' character indicating that zero-padding should be used
rather than blank-padding.  A `\-' overrides a `0' if both are used;
.El
.It "Field Width:"
An optional digit string specifying a
.Em field width ;
if the output string has fewer characters than the field width it will
be blank-padded on the left (or right, if the left-adjustment indicator
has been given) to make up the field width (note that a leading zero
is a flag, but an embedded zero is part of a field width);
.It Precision:
An optional period,
.Sq Cm \&.\& ,
followed by an optional digit string giving a
.Em precision
which specifies the number of digits to appear after the decimal point,
for
.Cm e
and 
.Cm f
formats, or the maximum number of characters to be printed
from a string; if the digit string is missing, the precision is treated
as zero;
.It Format:
A character which indicates the type of format to use (one of
.Cm diouxXfwEgGbcs ) .
.El
.Pp
A field width or precision may be
.Sq Cm \&*
instead of a digit string.
In this case an
.Ar argument
supplies the field width or precision.
.Pp
The format characters and their meanings are:
.Bl -tag -width Fl
.It Cm diouXx
The
.Ar argument
is printed as a signed decimal (d or i), unsigned octal, unsigned decimal,
or unsigned hexadecimal (X or x), respectively.
.It Cm f
The
.Ar argument
is printed in the style 
.Sm off
.Pf [\-]ddd Cm \&. No ddd
.Sm on
where the number of d's
after the decimal point is equal to the precision specification for
the argument.
If the precision is missing, 6 digits are given; if the precision
is explicitly 0, no digits and no decimal point are printed.
.It Cm eE
The
.Ar argument
is printed in the style 
.Sm off
.Pf [\-]d Cm \&. No ddd Cm e No \\*(Pmdd
.Sm on
where there
is one digit before the decimal point and the number after is equal to
the precision specification for the argument; when the precision is
missing, 6 digits are produced.
An upper-case E is used for an `E' format.
.It Cm gG
The
.Ar argument
is printed in style
.Cm f
or in style
.Cm e
.Pq Cm E
whichever gives full precision in minimum space.
.It Cm b
Characters from the string
.Ar argument
are printed with backslash-escape sequences expanded.
.It Cm c
The first character of
.Ar argument
is printed.
.It Cm s
Characters from the string
.Ar argument
are printed until the end is reached or until the number of characters
indicated by the precision specification is reached; however if the
precision is 0 or missing, all characters in the string are printed.
.It Cm \&%
Print a `%'; no argument is used.
.El
.Pp
In no case does a non-existent or small field width cause truncation of
a field; padding takes place only if the specified field width exceeds
the actual width.
.Sh RETURN VALUES
.Nm
exits 0 on success, 1 on failure.
.Sh SEE ALSO
.Xr echo 1 ,
.Xr printf 3
.Sh STANDARDS
The
.Nm
utility mostly conforms to 
.St -p1003.2-92 .
.Sh BUGS
Since the floating point numbers are translated from
.Tn ASCII
to floating-point and
then back again, floating-point precision may be lost.
.Pp
Parsing of - arguments is also somewhat different from
.Xr printf 3 ,
where unknown arguments are simply printed instead of being
flagged as errors.
Commit	Line	Data
44bd5ea7 A	1	.\" $NetBSD: printf.1,v 1.10 1998/08/22 14:54:48 garbled Exp $
	2	.\"
	3	.\" Copyright (c) 1989, 1990, 1993
	4	.\" The Regents of the University of California. All rights reserved.
	5	.\"
	6	.\" This code is derived from software contributed to Berkeley by
	7	.\" the Institute of Electrical and Electronics Engineers, Inc.
	8	.\"
	9	.\" Redistribution and use in source and binary forms, with or without
	10	.\" modification, are permitted provided that the following conditions
	11	.\" are met:
	12	.\" 1. Redistributions of source code must retain the above copyright
	13	.\" notice, this list of conditions and the following disclaimer.
	14	.\" 2. Redistributions in binary form must reproduce the above copyright
	15	.\" notice, this list of conditions and the following disclaimer in the
	16	.\" documentation and/or other materials provided with the distribution.
	17	.\" 3. All advertising materials mentioning features or use of this software
	18	.\" must display the following acknowledgement:
	19	.\" This product includes software developed by the University of
	20	.\" California, Berkeley and its contributors.
	21	.\" 4. Neither the name of the University nor the names of its contributors
	22	.\" may be used to endorse or promote products derived from this software
	23	.\" without specific prior written permission.
	24	.\"
	25	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	26	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	27	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	28	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	29	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	30	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	31	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	32	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	33	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	34	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	35	.\" SUCH DAMAGE.
	36	.\"
	37	.\" from: @(#)printf.1 8.1 (Berkeley) 6/6/93
	38	.\"
	39	.Dd November 5, 1993
	40	.Dt PRINTF 1
	41	.Os
	42	.Sh NAME
	43	.Nm printf
	44	.Nd formatted output
	45	.Sh SYNOPSIS
	46	.Nm
	47	.Ar format
	48	.Op Ar arguments ...
	49	.Sh DESCRIPTION
	50	.Nm
	51	formats and prints its arguments, after the first, under control
	52	of the
	53	.Ar format .
	54	The
	55	.Ar format
	56	is a character string which contains three types of objects: plain characters,
	57	which are simply copied to standard output, character escape sequences which
	58	are converted and copied to the standard output, and format specifications,
	59	each of which causes printing of the next successive
	60	.Ar argument .
	61	.Pp
	62	The
	63	.Ar arguments
	64	after the first are treated as strings if the corresponding format is
65	either
66	.Cm b ,
67	.Cm c
68	or
69	.Cm s ;
70	otherwise it is evaluated as a C constant, with the following extensions:
71	.Pp
72	.Bl -bullet -offset indent -compact
73	.It
74	A leading plus or minus sign is allowed.
75	.It
76	If the leading character is a single or double quote, the value is the
77	.Tn ASCII
78	code of the next character.
79	.El
80	.Pp
81	The format string is reused as often as necessary to satisfy the
82	.Ar arguments .
83	Any extra format specifications are evaluated with zero or the null
84	string.
85	.Pp
86	Character escape sequences are in backslash notation as defined in
87	.St -ansiC .
88	The characters and their meanings
89	are as follows:
90	.Bl -tag -width Ds -offset indent
91	.It Cm \ee
92	Write an <escape> character.
93	.It Cm \ea
94	Write a <bell> character.
95	.It Cm \eb
96	Write a <backspace> character.
97	.It Cm \ef
98	Write a <form-feed> character.
99	.It Cm \en
100	Write a <new-line> character.
101	.It Cm \er
102	Write a <carriage return> character.
103	.It Cm \et
104	Write a <tab> character.
105	.It Cm \ev
106	Write a <vertical tab> character.
107	.It Cm \e\'
108	Write a <single quote> character.
109	.It Cm \e\e
110	Write a backslash character.
111	.It Cm \e Ns Ar num
112	Write an 8-bit character whose
113	.Tn ASCII
114	value is the 1-, 2-, or 3-digit
115	octal number
116	.Ar num .
117	.El
118	.Pp
119	Each format specification is introduced by the percent character
120	(``%'').
121	The remainder of the format specification includes,
122	in the following order:
123	.Bl -tag -width Ds
124	.It "Zero or more of the following flags:"
125	.Bl -tag -width Ds
126	.It Cm #
127	A `#' character
128	specifying that the value should be printed in an ``alternative form''.
129	For
130	.Cm c ,
131	.Cm d ,
132	and
133	.Cm s ,
134	formats, this option has no effect. For the
135	.Cm o
136	formats the precision of the number is increased to force the first
137	character of the output string to a zero. For the
138	.Cm x
139	.Pq Cm X
140	format, a non-zero result has the string
141	.Li 0x
142	.Pq Li 0X
143	prepended to it. For
144	.Cm e ,
145	.Cm E ,
146	.Cm f ,
147	.Cm g ,
148	and
149	.Cm G ,
150	formats, the result will always contain a decimal point, even if no
151	digits follow the point (normally, a decimal point only appears in the
152	results of those formats if a digit follows the decimal point). For
153	.Cm g
154	and
155	.Cm G
156	formats, trailing zeros are not removed from the result as they
157	would otherwise be;
158	.It Cm \&\-
159	A minus sign `\-' which specifies
160	.Em left adjustment
161	of the output in the indicated field;
162	.It Cm \&+
163	A `+' character specifying that there should always be
164	a sign placed before the number when using signed formats.
165	.It Sq \&\ \&
166	A space specifying that a blank should be left before a positive number
167	for a signed format. A `+' overrides a space if both are used;
168	.It Cm \&0
169	A zero `0' character indicating that zero-padding should be used
170	rather than blank-padding. A `\-' overrides a `0' if both are used;
171	.El
172	.It "Field Width:"
173	An optional digit string specifying a
174	.Em field width ;
175	if the output string has fewer characters than the field width it will
176	be blank-padded on the left (or right, if the left-adjustment indicator
177	has been given) to make up the field width (note that a leading zero
178	is a flag, but an embedded zero is part of a field width);
179	.It Precision:
180	An optional period,
181	.Sq Cm \&.\& ,
182	followed by an optional digit string giving a
183	.Em precision
184	which specifies the number of digits to appear after the decimal point,
185	for
186	.Cm e
187	and
188	.Cm f
189	formats, or the maximum number of characters to be printed
190	from a string; if the digit string is missing, the precision is treated
191	as zero;
192	.It Format:
193	A character which indicates the type of format to use (one of
194	.Cm diouxXfwEgGbcs ) .
195	.El
196	.Pp
197	A field width or precision may be
198	.Sq Cm \&*
199	instead of a digit string.
200	In this case an
201	.Ar argument
202	supplies the field width or precision.
203	.Pp
204	The format characters and their meanings are:
205	.Bl -tag -width Fl
206	.It Cm diouXx
207	The
208	.Ar argument
209	is printed as a signed decimal (d or i), unsigned octal, unsigned decimal,
210	or unsigned hexadecimal (X or x), respectively.
211	.It Cm f
212	The
213	.Ar argument
214	is printed in the style
215	.Sm off
216	.Pf [\-]ddd Cm \&. No ddd
217	.Sm on
218	where the number of d's
219	after the decimal point is equal to the precision specification for
220	the argument.
221	If the precision is missing, 6 digits are given; if the precision
222	is explicitly 0, no digits and no decimal point are printed.
223	.It Cm eE
224	The
225	.Ar argument
226	is printed in the style
227	.Sm off
228	.Pf [\-]d Cm \&. No ddd Cm e No \\*(Pmdd
229	.Sm on
230	where there
231	is one digit before the decimal point and the number after is equal to
232	the precision specification for the argument; when the precision is
233	missing, 6 digits are produced.
234	An upper-case E is used for an `E' format.
235	.It Cm gG
236	The
237	.Ar argument
238	is printed in style
239	.Cm f
240	or in style
241	.Cm e
242	.Pq Cm E
243	whichever gives full precision in minimum space.
244	.It Cm b
245	Characters from the string
246	.Ar argument
247	are printed with backslash-escape sequences expanded.
248	.It Cm c
249	The first character of
250	.Ar argument
251	is printed.
252	.It Cm s
253	Characters from the string
254	.Ar argument
255	are printed until the end is reached or until the number of characters
256	indicated by the precision specification is reached; however if the
257	precision is 0 or missing, all characters in the string are printed.
258	.It Cm \&%
259	Print a `%'; no argument is used.
260	.El
261	.Pp
262	In no case does a non-existent or small field width cause truncation of
263	a field; padding takes place only if the specified field width exceeds
264	the actual width.
265	.Sh RETURN VALUES
266	.Nm
267	exits 0 on success, 1 on failure.
268	.Sh SEE ALSO
269	.Xr echo 1 ,
270	.Xr printf 3
271	.Sh STANDARDS
272	The
273	.Nm
9bafe280	274	utility mostly conforms to
44bd5ea7 A	275	.St -p1003.2-92 .
	276	.Sh BUGS
	277	Since the floating point numbers are translated from
	278	.Tn ASCII
	279	to floating-point and
	280	then back again, floating-point precision may be lost.
9bafe280 A	281	.Pp
	282	Parsing of - arguments is also somewhat different from
	283	.Xr printf 3 ,
	284	where unknown arguments are simply printed instead of being
	285	flagged as errors.