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PRINTF(1)		FreeBSD	General	Commands Manual		     PRINTF(1)

NAME
     printf -- formatted output

SYNOPSIS
     printf format [arguments ...]

DESCRIPTION
     The printf	utility	formats	and prints its arguments, after	the first,
     under control of the format.  The format is a character string which con-
     tains 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 argument.

     The arguments after the first are treated as strings if the corresponding
     format is either c, b or s; otherwise it is evaluated as a	C constant,
     with the following	extensions:

	   +o   A leading plus or minus sign is allowed.
	   +o   If the leading character	is a single or double quote, the value
	       is the character	code of	the next character.

     The format	string is reused as often as necessary to satisfy the
     arguments.	 Any extra format specifications are evaluated with zero or
     the null string.

     Character escape sequences	are in backslash notation as defined in	the
     ANSI X3.159-1989 (``ANSI C89''), with extensions.	The characters and
     their meanings are	as follows:

	   \a	   Write a <bell> character.
	   \b	   Write a <backspace> character.
	   \c	   Ignore remaining characters in this string.
	   \f	   Write a <form-feed> character.
	   \n	   Write a <new-line> character.
	   \r	   Write a <carriage return> character.
	   \t	   Write a <tab> character.
	   \v	   Write a <vertical tab> character.
	   \'	   Write a <single quote> character.
	   \\	   Write a backslash character.
	   \num	   Write a byte	whose value is the 1-, 2-, or 3-digit octal
		   number num.	Multibyte characters can be constructed	using
		   multiple \num sequences.

     Each format specification is introduced by	the percent character (``%'').
     The remainder of the format specification includes, in the	following
     order:

     Zero or more of the following flags:

	     #	     A `#' character specifying	that the value should be
		     printed in	an ``alternate form''.	For b, c, d, s and u
		     formats, this option has no effect.  For the o formats
		     the precision of the number is increased to force the
		     first character of	the output string to a zero.  For the
		     x (X) format, a non-zero result has the string 0x (0X)
		     prepended to it.  For a, A, e, E, f, F, g and 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 g	and G formats, trail-
		     ing zeros are not removed from the	result as they would
		     otherwise be;

	     -	     A minus sign `-' which specifies left adjustment of the
		     output in the indicated field;

	     +	     A `+' character specifying	that there should always be a
		     sign placed before	the number when	using signed formats.

	     ` '     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;

	     0	     A zero `0'	character indicating that zero-padding should
		     be	used rather than blank-padding.	 A `-' overrides a `0'
		     if	both are used;

     Field Width:
	     An	optional digit string specifying a field width;	if the output
	     string has	fewer bytes 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);

     Precision:
	     An	optional period, `.', followed by an optional digit string
	     giving a precision	which specifies	the number of digits to	appear
	     after the decimal point, for e and	f formats, or the maximum num-
	     ber of bytes to be	printed	from a string; if the digit string is
	     missing, the precision is treated as zero;

     Format:
	     A character which indicates the type of format to use (one	of
	     diouxXfFeEgGaAcsb).  The uppercase	formats	differ from their low-
	     ercase counterparts only in that the output of the	former is
	     entirely in uppercase.  The floating-point	format specifiers
	     (fFeEgGaA)	may be prefixed	by an L	to request that	additional
	     precision be used,	if available.

     A field width or precision	may be `*' instead of a	digit string.  In this
     case an argument supplies the field width or precision.

     The format	characters and their meanings are:

     diouXx	 The argument is printed as a signed decimal (d	or i),
		 unsigned octal, unsigned decimal, or unsigned hexadecimal (X
		 or x),	respectively.

     fF		 The argument is printed in the	style `[-]ddd.ddd' where the
		 number	of d's after the decimal point is equal	to the preci-
		 sion 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.	 The values
		 infinity and NaN are printed as `inf' and `nan', respec-
		 tively.

     eE		 The argument is printed in the	style e	`[-d.ddd+-dd]' where
		 there is one digit before the decimal point and the number
		 after is equal	to the precision specification for the argu-
		 ment; when the	precision is missing, 6	digits are produced.
		 The values infinity and NaN are printed as `inf' and `nan',
		 respectively.

     gG		 The argument is printed in style f (F)	or in style e (E)
		 whichever gives full precision	in minimum space.

     aA		 The argument is printed in style `[-h.hhh+-pd]' where there
		 is one	digit before the hexadecimal point and the number
		 after is equal	to the precision specification for the argu-
		 ment; when the	precision is missing, enough digits are	pro-
		 duced to convey the argument's	exact double-precision float-
		 ing-point representation.  The	values infinity	and NaN	are
		 printed as `inf' and `nan', respectively.

     c		 The first byte	of argument is printed.

     s		 Bytes from the	string argument	are printed until the end is
		 reached or until the number of	bytes indicated	by the preci-
		 sion specification is reached;	however	if the precision is 0
		 or missing, the string	is printed entirely.

     b		 As for	s, but interpret character escapes in backslash	nota-
		 tion in the string argument.  The permitted escape sequences
		 are slightly different	in that	octal escapes are \0num
		 instead of \num.

     %		 Print a `%'; no argument is used.

     The decimal point character is defined in the program's locale (category
     LC_NUMERIC).

     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.

     Some shells may provide a builtin printf command which is similar or
     identical to this utility.	 Consult the builtin(1)	manual page.

EXIT STATUS
     The printf	utility	exits 0	on success, and	>0 if an error occurs.

COMPATIBILITY
     The traditional BSD behavior of converting	arguments of numeric formats
     not beginning with	a digit	to the ASCII code of the first character is
     not supported.

SEE ALSO
     builtin(1), echo(1), sh(1), printf(3)

STANDARDS
     The printf	command	is expected to be compatible with the IEEE Std 1003.2
     (``POSIX.2'') specification.

HISTORY
     The printf	command	appeared in 4.3BSD-Reno.  It is	modeled	after the
     standard library function,	printf(3).

CAVEATS
     ANSI hexadecimal character	constants were deliberately not	provided.

     Trying to print a dash ("-") as the first character causes	printf to
     interpret the dash	as a program argument.	-- must	be used	before format.

     If	the locale contains multibyte characters (such as UTF-8), the c	format
     and b and s formats with a	precision may not operate as expected.

BUGS
     Since the floating	point numbers are translated from ASCII	to floating-
     point and then back again,	floating-point precision may be	lost.  (By
     default, the number is translated to an IEEE-754 double-precision value
     before being printed.  The	L modifier may produce additional precision,
     depending on the hardware platform.)

     The escape	sequence \000 is the string terminator.	 When present in the
     argument for the b	format,	the argument will be truncated at the \000
     character.

     Multibyte characters are not recognized in	format strings (this is	only a
     problem if	`%' can	appear inside a	multibyte character).

FreeBSD	10.3			 May 28, 2011			  FreeBSD 10.3

NAME | SYNOPSIS | DESCRIPTION | EXIT STATUS | COMPATIBILITY | SEE ALSO | STANDARDS | HISTORY | CAVEATS | BUGS

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