1.\" Copyright (c) 1989, 1990, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" the Institute of Electrical and Electronics Engineers, Inc. 6.\" 7.\" Redistribution and use in source and binary forms, with or without 8.\" modification, are permitted provided that the following conditions 9.\" are met: 10.\" 1. Redistributions of source code must retain the above copyright 11.\" notice, this list of conditions and the following disclaimer. 12.\" 2. Redistributions in binary form must reproduce the above copyright 13.\" notice, this list of conditions and the following disclaimer in the 14.\" documentation and/or other materials provided with the distribution. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" @(#)printf.1 8.1 (Berkeley) 6/6/93 36.\" $FreeBSD: src/usr.bin/printf/printf.1,v 1.8.2.7 2002/07/15 07:37:49 keramida Exp $ 37.\" $DragonFly: src/usr.bin/printf/printf.1,v 1.2 2003/06/17 04:29:30 dillon Exp $ 38.\" 39.Dd June 6, 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 Op Ar arguments ... 48.Sh DESCRIPTION 49The 50.Nm 51utility formats 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 c , b 67or 68.Cm s ; 69otherwise it is evaluated as a C constant, with the following extensions: 70.Pp 71.Bl -bullet -offset indent -compact 72.It 73A leading plus or minus sign is allowed. 74.It 75If the leading character is a single or double quote, the value is the 76.Tn ASCII 77code of the next character. 78.El 79.Pp 80The format string is reused as often as necessary to satisfy the 81.Ar arguments . 82Any extra format specifications are evaluated with zero or the null 83string. 84.Pp 85Character escape sequences are in backslash notation as defined in the 86.St -ansiC , 87with extensions. 88The characters and their meanings 89are as follows: 90.Pp 91.Bl -tag -width Ds -offset indent -compact 92.It Cm \ea 93Write a <bell> character. 94.It Cm \eb 95Write a <backspace> character. 96.It Cm \ec 97Ignore remaining characters in this string. 98.It Cm \ef 99Write a <form-feed> character. 100.It Cm \en 101Write a <new-line> character. 102.It Cm \er 103Write a <carriage return> character. 104.It Cm \et 105Write a <tab> character. 106.It Cm \ev 107Write a <vertical tab> character. 108.It Cm \e\' 109Write a <single quote> character. 110.It Cm \e\e 111Write a backslash character. 112.It Cm \e Ns Ar num 113.It Cm \e0 Ns Ar num 114Write an 8-bit character whose 115.Tn ASCII 116value is the 1-, 2-, or 3-digit 117octal number 118.Ar num . 119.El 120.Pp 121Each format specification is introduced by the percent character 122(``%''). 123The remainder of the format specification includes, 124in the following order: 125.Bl -tag -width Ds 126.It "Zero or more of the following flags:" 127.Bl -tag -width Ds 128.It Cm # 129A `#' character 130specifying that the value should be printed in an ``alternate form''. 131For 132.Cm c , d , 133and 134.Cm s , 135formats, this option has no effect. For the 136.Cm o 137formats the precision of the number is increased to force the first 138character of the output string to a zero. For the 139.Cm x 140.Pq Cm X 141format, a non-zero result has the string 142.Li 0x 143.Pq Li 0X 144prepended to it. For 145.Cm e , E , f , g , 146and 147.Cm G , 148formats, the result will always contain a decimal point, even if no 149digits follow the point (normally, a decimal point only appears in the 150results of those formats if a digit follows the decimal point). For 151.Cm g 152and 153.Cm G 154formats, trailing zeros are not removed from the result as they 155would otherwise be; 156.It Cm \&\- 157A minus sign `\-' which specifies 158.Em left adjustment 159of the output in the indicated field; 160.It Cm \&+ 161A `+' character specifying that there should always be 162a sign placed before the number when using signed formats. 163.It Sq \&\ \& 164A space specifying that a blank should be left before a positive number 165for a signed format. A `+' overrides a space if both are used; 166.It Cm \&0 167A zero `0' character indicating that zero-padding should be used 168rather than blank-padding. A `\-' overrides a `0' if both are used; 169.El 170.It "Field Width:" 171An optional digit string specifying a 172.Em field width ; 173if the output string has fewer characters than the field width it will 174be blank-padded on the left (or right, if the left-adjustment indicator 175has been given) to make up the field width (note that a leading zero 176is a flag, but an embedded zero is part of a field width); 177.It Precision: 178An optional period, 179.Sq Cm \&.\& , 180followed by an optional digit string giving a 181.Em precision 182which specifies the number of digits to appear after the decimal point, 183for 184.Cm e 185and 186.Cm f 187formats, or the maximum number of characters to be printed 188from a string; if the digit string is missing, the precision is treated 189as zero; 190.It Format: 191A character which indicates the type of format to use (one of 192.Cm diouxXfwEgGcsb ) . 193.El 194.Pp 195A field width or precision may be 196.Sq Cm \&* 197instead of a digit string. 198In this case an 199.Ar argument 200supplies the field width or precision. 201.Pp 202The format characters and their meanings are: 203.Bl -tag -width Fl 204.It Cm diouXx 205The 206.Ar argument 207is printed as a signed decimal (d or i), unsigned octal, unsigned decimal, 208or unsigned hexadecimal (X or x), respectively. 209.It Cm f 210The 211.Ar argument 212is printed in the style `[\-]ddd.ddd' where the number of d's 213after the decimal point is equal to the precision specification for 214the argument. 215If the precision is missing, 6 digits are given; if the precision 216is explicitly 0, no digits and no decimal point are printed. 217.It Cm eE 218The 219.Ar argument 220is printed in the style 221.Cm e 222.Sm off 223.Sq Op - Ar d.ddd No \(+- Ar dd 224.Sm on 225where there 226is one digit before the decimal point and the number after is equal to 227the precision specification for the argument; when the precision is 228missing, 6 digits are produced. 229An upper-case E is used for an `E' format. 230.It Cm gG 231The 232.Ar argument 233is printed in style 234.Cm f 235or in style 236.Cm e 237.Pq Cm E 238whichever gives full precision in minimum space. 239.It Cm c 240The first character of 241.Ar argument 242is printed. 243.It Cm s 244Characters from the string 245.Ar argument 246are printed until the end is reached or until the number of characters 247indicated by the precision specification is reached; however if the 248precision is 0 or missing, all characters in the string are printed. 249.It Cm b 250As for 251.Cm s , 252but interpret character escapes in backslash notation in the string 253.Ar argument . 254.It Cm \&% 255Print a `%'; no argument is used. 256.El 257.Pp 258The decimal point 259character is defined in the program's locale (category 260.Dv LC_NUMERIC ) . 261.Pp 262In no case does a non-existent or small field width cause truncation of 263a field; padding takes place only if the specified field width exceeds 264the actual width. 265.Sh DIAGNOSTICS 266.Ex -std 267.Sh COMPATIBILITY 268The traditional 269.Bx 270behavior of converting arguments of numeric formats not beginning 271with a digit to the 272.Tn ASCII 273code of the first character is not supported. 274.Sh SEE ALSO 275.Xr echo 1 , 276.Xr printf 3 277.Sh STANDARDS 278The 279.Nm 280command is expected to be compatible with the 281.St -p1003.2 282specification. 283.Sh HISTORY 284The 285.Nm 286command appeared in 287.Bx 4.3 Reno . 288It is modeled 289after the standard library function, 290.Xr printf 3 . 291.Sh BUGS 292Since the floating point numbers are translated from 293.Tn ASCII 294to floating-point and 295then back again, floating-point precision may be lost. 296.Pp 297.Tn ANSI 298hexadecimal character constants were deliberately not provided. 299.Pp 300The escape sequence \e000 is the string terminator. When present in the 301.Ar format , 302the 303.Ar format 304will be truncated at the \e000 character. 305