1.\" $NetBSD: printf.1,v 1.16 2002/09/30 11:09:09 grant 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 51formats and prints its arguments, after the first, under control 52of the 53.Ar format . 54The 55.Ar format 56is a character string which contains three types of objects: plain characters, 57which are simply copied to standard output, character escape sequences which 58are converted and copied to the standard output, and format specifications, 59each of which causes printing of the next successive 60.Ar argument . 61.Pp 62The 63.Ar arguments 64after the first are treated as strings if the corresponding format is 65either 66.Cm b , 67.Cm c 68or 69.Cm s ; 70otherwise it is evaluated as a C constant, with the following extensions: 71.Pp 72.Bl -bullet -offset indent -compact 73.It 74A leading plus or minus sign is allowed. 75.It 76If the leading character is a single or double quote, the value is the 77.Tn ASCII 78code of the next character. 79.El 80.Pp 81The format string is reused as often as necessary to satisfy the 82.Ar arguments . 83Any extra format specifications are evaluated with zero or the null 84string. 85.Pp 86Character escape sequences are in backslash notation as defined in 87.St -ansiC . 88The characters and their meanings 89are as follows: 90.Bl -tag -width Ds -offset indent 91.It Cm \ee 92Write an \*[Lt]escape\*[Gt] character. 93.It Cm \ea 94Write a \*[Lt]bell\*[Gt] character. 95.It Cm \eb 96Write a \*[Lt]backspace\*[Gt] character. 97.It Cm \ef 98Write a \*[Lt]form-feed\*[Gt] character. 99.It Cm \en 100Write a \*[Lt]new-line\*[Gt] character. 101.It Cm \er 102Write a \*[Lt]carriage return\*[Gt] character. 103.It Cm \et 104Write a \*[Lt]tab\*[Gt] character. 105.It Cm \ev 106Write a \*[Lt]vertical tab\*[Gt] character. 107.It Cm \e\' 108Write a \*[Lt]single quote\*[Gt] character. 109.It Cm \e\e 110Write a backslash character. 111.It Cm \e Ns Ar num 112Write an 8-bit character whose 113.Tn ASCII 114value is the 1-, 2-, or 3-digit 115octal number 116.Ar num . 117.El 118.Pp 119Each format specification is introduced by the percent character 120(``%''). 121The remainder of the format specification includes, 122in 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 # 127A `#' character 128specifying that the value should be printed in an ``alternative form''. 129For 130.Cm c , 131.Cm d , 132and 133.Cm s , 134formats, this option has no effect. 135For the 136.Cm o 137formats the precision of the number is increased to force the first 138character of the output string to a zero. 139For the 140.Cm x 141.Pq Cm X 142format, a non-zero result has the string 143.Li 0x 144.Pq Li 0X 145prepended to it. 146For 147.Cm e , 148.Cm E , 149.Cm f , 150.Cm g , 151and 152.Cm G , 153formats, the result will always contain a decimal point, even if no 154digits follow the point (normally, a decimal point only appears in the 155results of those formats if a digit follows the decimal point). 156For 157.Cm g 158and 159.Cm G 160formats, trailing zeros are not removed from the result as they 161would otherwise be; 162.It Cm \&\- 163A minus sign `\-' which specifies 164.Em left adjustment 165of the output in the indicated field; 166.It Cm \&+ 167A `+' character specifying that there should always be 168a sign placed before the number when using signed formats. 169.It Sq \&\ \& 170A space specifying that a blank should be left before a positive number 171for a signed format. 172A `+' overrides a space if both are used; 173.It Cm \&0 174A zero `0' character indicating that zero-padding should be used 175rather than blank-padding. 176A `\-' overrides a `0' if both are used; 177.El 178.It "Field Width:" 179An optional digit string specifying a 180.Em field width ; 181if the output string has fewer characters than the field width it will 182be blank-padded on the left (or right, if the left-adjustment indicator 183has been given) to make up the field width (note that a leading zero 184is a flag, but an embedded zero is part of a field width); 185.It Precision : 186An optional period, 187.Sq Cm \&.\& , 188followed by an optional digit string giving a 189.Em precision 190which specifies the number of digits to appear after the decimal point, 191for 192.Cm e 193and 194.Cm f 195formats, or the maximum number of characters to be printed 196from a string; if the digit string is missing, the precision is treated 197as zero; 198.It Format : 199A character which indicates the type of format to use (one of 200.Cm diouxXfwEgGbcs ) . 201.El 202.Pp 203A field width or precision may be 204.Sq Cm \&* 205instead of a digit string. 206In this case an 207.Ar argument 208supplies the field width or precision. 209.Pp 210The format characters and their meanings are: 211.Bl -tag -width Fl 212.It Cm diouXx 213The 214.Ar argument 215is printed as a signed decimal (d or i), unsigned octal, unsigned decimal, 216or unsigned hexadecimal (X or x), respectively. 217.It Cm f 218The 219.Ar argument 220is printed in the style 221.Sm off 222.Pf [\-]ddd Cm \&. No ddd 223.Sm on 224where the number of d's 225after the decimal point is equal to the precision specification for 226the argument. 227If the precision is missing, 6 digits are given; if the precision 228is explicitly 0, no digits and no decimal point are printed. 229.It Cm eE 230The 231.Ar argument 232is printed in the style 233.Sm off 234.Pf [\-]d Cm \&. No ddd Cm e No \\*(Pmdd 235.Sm on 236where there 237is one digit before the decimal point and the number after is equal to 238the precision specification for the argument; when the precision is 239missing, 6 digits are produced. 240An upper-case E is used for an `E' format. 241.It Cm gG 242The 243.Ar argument 244is printed in style 245.Cm f 246or in style 247.Cm e 248.Pq Cm E 249whichever gives full precision in minimum space. 250.It Cm b 251Characters from the string 252.Ar argument 253are printed with backslash-escape sequences expanded. 254.It Cm c 255The first character of 256.Ar argument 257is printed. 258.It Cm s 259Characters from the string 260.Ar argument 261are printed until the end is reached or until the number of characters 262indicated by the precision specification is reached; however if the 263precision is 0 or missing, all characters in the string are printed. 264.It Cm \&% 265Print a `%'; no argument is used. 266.El 267.Pp 268In no case does a non-existent or small field width cause truncation of 269a field; padding takes place only if the specified field width exceeds 270the actual width. 271.Sh EXIT STATUS 272.Nm 273exits 0 on success, 1 on failure. 274.Sh SEE ALSO 275.Xr echo 1 , 276.Xr printf 3 , 277.Xr printf 9 278.Sh STANDARDS 279The 280.Nm 281utility conforms to 282.St -p1003.2-92 . 283.Sh BUGS 284Since the floating point numbers are translated from 285.Tn ASCII 286to floating-point and 287then back again, floating-point precision may be lost. 288