formats(5)						Standards, Environments, and Macros						formats(5)

NAME

       formats - file format notation

DESCRIPTION

       Utility	descriptions  use  a syntax to describe the data organization within files--stdin, stdout, stderr, input files, and output files--
       when that organization is not otherwise obvious. The syntax is similar to that used by the  printf(3C) function.  When used  for  stdin	or
       input  file  descriptions, this syntax describes the format that could have been used to write the text to be read, not a format that could
       be used by the  scanf(3C) function to read the input file.

   Format
       The description of an individual record is as follows:

       "<format>", [<arg1>, <arg2>, ..., <argn>]

       The format is a character string that contains three types of objects defined below:

       characters	       Characters that are not escape sequences or conversion specifications, as described below, are copied to  the  out-
			       put.

       escape sequences        Represent non-graphic characters.

       conversion specificationSpecifies the output format of each argument. (See below.)

       The following characters have the following special meaning in the format string:

       `` ''		       (An empty character position.) One or more blank characters.

       /		       Exactly one space character.

       The  notation  for spaces allows some flexibility for application output. Note that an empty character position in format represents one or
       more blank characters on the output (not white space, which can include newline characters). Therefore, another	utility  that  reads  that
       output as its input must be prepared to parse the data using scanf(3C), awk(1), and so forth. The  character is used when exactly one space
       character is output.

   Escape Sequences
       The following table lists escape sequences and  associated actions on display devices capable of the action.

	 Sequence	 Character	Terminal Action
	    \	      backslash 	None.
	    a	      alert		Attempts  to  alert  the   user
					through   audible   or	visible
					notification.
	    	      backspace 	Moves the printing position  to
					one  column  before the current
					position,  unless  the	current
					position  is  the  start  of  a
					line.

	    f	      form-feed 	Moves the printing position  to
					the  initial  printing position
					of the next logical page.
	    
	      newline		Moves the printing position  to
					the start of the next line.
	    
	      carriage-return	Moves  the printing position to
					the start of the current line.
	    		      tab		Moves the printing position  to
					the  next  tab	position on the
					current line. If there	are  no
					more  tab positions left on the
					line,  the  behavior  is  unde-
					fined.
	    v	      vertical-tab	Moves  the printing position to
					the start of the next  vertical
					tab  position.	If there are no
					more  vertical	tab   positions
					left  on the page, the behavior
					is undefined.

   Conversion Specifications
       Each conversion specification is introduced by the percent-sign character (%). After the character %, the following appear in sequence:

       flags		       Zero or more flags, in any order, that modify the meaning of the conversion specification.

       field width	       An optional string of decimal digits to specify a minimum field width. For an output field, if the converted  value
			       has  fewer  bytes  than	the  field  width,  it	is  padded on the left (or right, if the left-adjustment flag (-),
			       described below, has been given to the field width).

       precision	       Gives the minimum number of digits to appear for the d, o, i, u, x or X conversions (the field is padded with lead-
			       ing  zeros), the number of digits to appear after the radix character for the e and f conversions, the maximum num-
			       ber of significant digits for the g conversion; or the maximum number of bytes to be written from  a  string  in  s
			       conversion. The precision takes the form of a period (.) followed by a decimal digit string; a null digit string is
			       treated as zero.

       conversion characters   A conversion character (see below) that indicates the type of conversion to be applied.

   flags
       The flags and their meanings are:

       -	       The result of the conversion is left-justified within the field.

       +	       The result of a signed conversion always begins with a sign (+ or -).

       <space>	       If the first character of a signed conversion is not a sign, a space character is prefixed to the result. This  means  that
		       if the space character and + flags both appear, the space character flag is ignored.

       #	       The  value  is to be converted to an alternative form. For c, d, i, u, and s conversions, the behaviour is undefined. For o
		       conversion, it increases the precision to force the first digit of the result to be a zero. For x or X conversion,  a  non-
		       zero  result  has  0x  or  0X prefixed to it, respectively. For e, E, f, g, and G conversions, the result always contains a
		       radix character, even if no digits follow the radix character. For g and G conversions, trailing zeros are not removed from
		       the result as they usually are.

       0	       For  d,	i, o, u, x, X, e, E, f, g, and G conversions, leading zeros (following any indication of sign or base) are used to
		       pad to the field width; no space padding is performed. If the 0 and - flags both appear, the 0 flag is ignored. For  d,	i,
		       o,  u,  x  and  X  conversions, if a precision is specified, the 0 flag is ignored. For other conversions, the behaviour is
		       undefined.

   Conversion Characters
       Each conversion character results in fetching zero or more arguments. The results are undefined if there are insufficient arguments for the
       format. If the format is exhausted while arguments remain, the excess arguments are ignored.

       The conversion characters and their meanings are:

       d,i,o,u,x,X     The integer argument is written as signed decimal (d or i), unsigned octal (o), unsigned decimal (u), or unsigned hexadeci-
		       mal notation (x and X). The d and i specifiers convert to signed decimal in the style [-]dddd. The x  conversion  uses  the
		       numbers and letters 0123456789abcdef and the X conversion uses the numbers and letters 0123456789ABCDEF. The precision com-
		       ponent of the argument specifies the minimum number of digits to appear. If the value being converted can be represented in
		       fewer  digits than the specified minimum, it is expanded with leading zeros. The default precision is 1. The result of con-
		       verting a zero value with a precision of 0 is no characters. If both the field width and precision are omitted, the  imple-
		       mentation  may precede, follow or precede and follow numeric arguments of types d, i and u with blank characters; arguments
		       of type o (octal) may be preceded with leading zeros.

		       The treatment of integers and spaces is different from the printf(3C) function in that they can be  surrounded  with  blank
		       characters. This was done so that, given a format such as:

		       "%d
",<foo>

		       the implementation could use a printf() call such as:

		       printf("%6d
", foo);

		       and still conform. This notation is thus somewhat like scanf() in addition to printf().

       f	       The floating point number argument is written in decimal notation in the style [-]ddd.ddd, where the number of digits after
		       the radix character (shown here as a decimal point) is equal to the precision specification. The LC_NUMERIC locale category
		       determines the radix character to use in this format. If the precision is omitted from the argument, six digits are written
		       after the radix character; if the precision is explicitly 0, no radix character appears.

       e,E	       The floating point number argument is written in the style [-]d.ddde+-dd (the symbol +- indicates either a  plus  or  minus
		       sign),  where  there is one digit before the radix character (shown here as a decimal point) and the number of digits after
		       it is equal to the precision. The  LC_NUMERIC locale category determines the radix character to use in  this  format.  When
		       the  precision  is  missing,  six  digits are  written after the radix character; if the precision is 0, no radix character
		       appears. The E conversion character produces a number with E instead of e introducing the  exponent.  The  exponent  always
		       contains  at least two digits. However, if the value to be written requires an exponent greater than two digits, additional
		       exponent digits are written as necessary.

       g,G	       The floating point number argument is written in style f or e (or in style E in the case of a G conversion character), with
		       the  precision  specifying the number of significant digits. The style used depends on the value converted: style g is used
		       only if the exponent resulting from the conversion is less than -4 or greater than or  equal  to  the  precision.  Trailing
		       zeros are removed from the result. A radix character appears only if it is followed by a digit.

       c	       The integer argument is converted to an unsigned char and the resulting byte is written.

       s	       The  argument  is  taken  to be a string and bytes from the string are written until the end of the string or the number of
		       bytes indicated by the precision specification of the argument is reached.  If the precision is omitted from the  argument,
		       it is taken to be infinite, so all bytes up to the end of the string are written.

       %	       Write a % character; no argument is converted.

       In  no  case  does  a non-existent or insufficient field width cause truncation of a field; if the result of a conversion is wider than the
       field width, the field is simply expanded to contain the conversion result. The term field width should not be confused with the term  pre-
       cision used in the description of %s.

       One  difference	from  the  C function printf() is that the l and h conversion characters are not used. There is no differentiation between
       decimal values for type int, type  long, or type  short. The specifications %d or %i should be interpreted as an arbitrary length  sequence
       of  digits.  Also,  no  distinction is made between single precision and double precision numbers (float or double in C).  These are simply
       referred to as floating point numbers.

       Many of the output descriptions	use the term line, such as:

       "%s", <input line>

       Since the definition of line includes the trailing newline character already, there is no need to include a 
 in the format; a double new-
       line character would otherwise result.

EXAMPLES

       Example	1: To represent the output of a program that prints a date and time in the form Sunday, July 3, 10:02, where <weekday> and <month>
       are strings:

       "%s,/\%s/\%d,/\%d:%.2d
",<weekday>,<month>,<day>,<hour>,<min>

       Example 2: To show pi written to 5 decimal places:

       "pi/=/\%.5f
",<value of pi>

       Example 3: To show an input file format consisting of five colon-separated fields:

       "%s:%s:%s:%s:%s
",<arg1>,<arg2>,<arg3>,<arg4>,<arg5>

SEE ALSO

       awk(1), printf(1), printf(3C), scanf(3C)

SunOS 5.10							    28 Mar 1995 							formats(5)