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.\" 38.Dd June 6, 1993 39.Dt PRINTF 1 40.Os 41.Sh NAME 42.Nm printf 43.Nd formatted output 44.Sh SYNOPSIS 45.Nm 46.Ar format Op Ar arguments ... 47.Sh DESCRIPTION 48The 49.Nm 50utility formats and prints its arguments, after the first, under control 51of the 52.Ar format . 53The 54.Ar format 55is a character string which contains three types of objects: plain characters, 56which are simply copied to standard output, character escape sequences which 57are converted and copied to the standard output, and format specifications, 58each of which causes printing of the next successive 59.Ar argument . 60.Pp 61The 62.Ar arguments 63after the first are treated as strings if the corresponding format is 64either 65.Cm c , b 66or 67.Cm s ; 68otherwise it is evaluated as a C constant, with the following extensions: 69.Pp 70.Bl -bullet -offset indent -compact 71.It 72A leading plus or minus sign is allowed. 73.It 74If the leading character is a single or double quote, the value is the 75.Tn ASCII 76code of the next character. 77.El 78.Pp 79The format string is reused as often as necessary to satisfy the 80.Ar arguments . 81Any extra format specifications are evaluated with zero or the null 82string. 83.Pp 84Character escape sequences are in backslash notation as defined in the 85.St -ansiC , 86with extensions. 87The characters and their meanings 88are as follows: 89.Pp 90.Bl -tag -width Ds -offset indent -compact 91.It Cm \ea 92Write a <bell> character. 93.It Cm \eb 94Write a <backspace> character. 95.It Cm \ec 96Ignore remaining characters in this string. 97.It Cm \ef 98Write a <form-feed> character. 99.It Cm \en 100Write a <new-line> character. 101.It Cm \er 102Write a <carriage return> character. 103.It Cm \et 104Write a <tab> character. 105.It Cm \ev 106Write a <vertical tab> character. 107.It Cm \e\' 108Write a <single quote> character. 109.It Cm \e\e 110Write a backslash character. 111.It Cm \e Ns Ar num 112.It Cm \e0 Ns Ar num 113Write an 8-bit character whose 114.Tn ASCII 115value is the 1-, 2-, or 3-digit 116octal number 117.Ar num . 118.El 119.Pp 120Each format specification is introduced by the percent character 121(``%''). 122The remainder of the format specification includes, 123in the following order: 124.Bl -tag -width Ds 125.It "Zero or more of the following flags:" 126.Bl -tag -width Ds 127.It Cm # 128A `#' character 129specifying that the value should be printed in an ``alternate form''. 130For 131.Cm c , d , 132and 133.Cm s , 134formats, this option has no effect. For the 135.Cm o 136formats the precision of the number is increased to force the first 137character of the output string to a zero. For the 138.Cm x 139.Pq Cm X 140format, a non-zero result has the string 141.Li 0x 142.Pq Li 0X 143prepended to it. For 144.Cm e , E , f , g , 145and 146.Cm G , 147formats, the result will always contain a decimal point, even if no 148digits follow the point (normally, a decimal point only appears in the 149results of those formats if a digit follows the decimal point). For 150.Cm g 151and 152.Cm G 153formats, trailing zeros are not removed from the result as they 154would otherwise be; 155.It Cm \&\- 156A minus sign `\-' which specifies 157.Em left adjustment 158of the output in the indicated field; 159.It Cm \&+ 160A `+' character specifying that there should always be 161a sign placed before the number when using signed formats. 162.It Sq \&\ \& 163A space specifying that a blank should be left before a positive number 164for a signed format. A `+' overrides a space if both are used; 165.It Cm \&0 166A zero `0' character indicating that zero-padding should be used 167rather than blank-padding. A `\-' overrides a `0' if both are used; 168.El 169.It "Field Width:" 170An optional digit string specifying a 171.Em field width ; 172if the output string has fewer characters than the field width it will 173be blank-padded on the left (or right, if the left-adjustment indicator 174has been given) to make up the field width (note that a leading zero 175is a flag, but an embedded zero is part of a field width); 176.It Precision: 177An optional period, 178.Sq Cm \&.\& , 179followed by an optional digit string giving a 180.Em precision 181which specifies the number of digits to appear after the decimal point, 182for 183.Cm e 184and 185.Cm f 186formats, or the maximum number of characters to be printed 187from a string; if the digit string is missing, the precision is treated 188as zero; 189.It Format: 190A character which indicates the type of format to use (one of 191.Cm diouxXfwEgGcsb ) . 192.El 193.Pp 194A field width or precision may be 195.Sq Cm \&* 196instead of a digit string. 197In this case an 198.Ar argument 199supplies the field width or precision. 200.Pp 201The format characters and their meanings are: 202.Bl -tag -width Fl 203.It Cm diouXx 204The 205.Ar argument 206is printed as a signed decimal (d or i), unsigned octal, unsigned decimal, 207or unsigned hexadecimal (X or x), respectively. 208.It Cm f 209The 210.Ar argument 211is printed in the style `[\-]ddd.ddd' where the number of d's 212after the decimal point is equal to the precision specification for 213the argument. 214If the precision is missing, 6 digits are given; if the precision 215is explicitly 0, no digits and no decimal point are printed. 216.It Cm eE 217The 218.Ar argument 219is printed in the style 220.Cm e 221.Sm off 222.Sq Op - Ar d.ddd No \(+- Ar dd 223.Sm on 224where there 225is one digit before the decimal point and the number after is equal to 226the precision specification for the argument; when the precision is 227missing, 6 digits are produced. 228An upper-case E is used for an `E' format. 229.It Cm gG 230The 231.Ar argument 232is printed in style 233.Cm f 234or in style 235.Cm e 236.Pq Cm E 237whichever gives full precision in minimum space. 238.It Cm c 239The first character of 240.Ar argument 241is printed. 242.It Cm s 243Characters from the string 244.Ar argument 245are printed until the end is reached or until the number of characters 246indicated by the precision specification is reached; however if the 247precision is 0 or missing, all characters in the string are printed. 248.It Cm b 249As for 250.Cm s , 251but interpret character escapes in backslash notation in the string 252.Ar argument . 253.It Cm \&% 254Print a `%'; no argument is used. 255.El 256.Pp 257The decimal point 258character is defined in the program's locale (category 259.Dv LC_NUMERIC ) . 260.Pp 261In no case does a non-existent or small field width cause truncation of 262a field; padding takes place only if the specified field width exceeds 263the actual width. 264.Sh DIAGNOSTICS 265.Ex -std 266.Sh COMPATIBILITY 267The traditional 268.Bx 269behavior of converting arguments of numeric formats not beginning 270with a digit to the 271.Tn ASCII 272code of the first character is not supported. 273.Sh SEE ALSO 274.Xr echo 1 , 275.Xr printf 3 276.Sh STANDARDS 277The 278.Nm 279command is expected to be compatible with the 280.St -p1003.2 281specification. 282.Sh HISTORY 283The 284.Nm 285command appeared in 286.Bx 4.3 Reno . 287It is modeled 288after the standard library function, 289.Xr printf 3 . 290.Sh BUGS 291Since the floating point numbers are translated from 292.Tn ASCII 293to floating-point and 294then back again, floating-point precision may be lost. 295.Pp 296.Tn ANSI 297hexadecimal character constants were deliberately not provided. 298.Pp 299The escape sequence \e000 is the string terminator. When present in the 300.Ar format , 301the 302.Ar format 303will be truncated at the \e000 character. 304