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

     printf -- formatted output

     printf format [arguments ...]

     The printf	utility	formats	and prints its arguments, after	the first, un-
     der 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.
	   \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 or-

     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);

	     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;

	     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 en-
	     tirely 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), un-
		 signed	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-

     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',

     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 af-
		 ter is	equal to the precision specification for the argument;
		 when the precision is missing,	enough digits are produced to
		 convey	the argument's exact double-precision floating-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	in-
		 stead of \num and that	an additional escape sequence \c stops
		 further output	from this printf invocation.

     n$		 Allows	reordering of the output according to argument.

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

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

     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.

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

     Print the string "hello":

	   $ printf "%s\n" hello

     Same as above, but	notice that the	format string is not quoted and	hence
     we	do not get the expected	behavior:

	   $ printf %s\n hello

     Print arguments forcing sign only for the first argument:

	   $ printf "%+d\n%d\n%d\n" 1 -2 13

     Same as above, but	the single format string will be applied to the	three

	   $ printf "%+d\n" 1 -2 13

     Print number using	only two digits	after the decimal point:

	   $ printf "%.2f\n" 31.7456

     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.

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

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

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

     ANSI hexadecimal character	constants were deliberately not	provided.

     Trying to print a dash ("-") as the first character causes	printf to in-
     terpret 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.

     Since the floating	point numbers are translated from ASCII	to floating-
     point and then back again,	floating-point precision may be	lost.  (By de-
     fault, the	number is translated to	an IEEE-754 double-precision value be-
     fore being	printed.  The L	modifier may produce additional	precision, de-
     pending 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

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

FreeBSD	13.0			 July 1, 2020			  FreeBSD 13.0


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