
PRINTF(1)                 BSD General Commands Manual                PRINTF(1)

NNAAMMEE
     pprriinnttff -- formatted output

SSYYNNOOPPSSIISS
     pprriinnttff _f_o_r_m_a_t [_a_r_g_u_m_e_n_t_s _._._.]

DDEESSCCRRIIPPTTIIOONN
     The pprriinnttff utility formats and prints its arguments, after the first,
     under control of the _f_o_r_m_a_t.  The _f_o_r_m_a_t 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 _a_r_g_u_m_e_n_t.

     The _a_r_g_u_m_e_n_t_s after the first are treated as strings if the corresponding
     format is either cc, bb or ss; otherwise it is evaluated as a C constant,
     with the following extensions:

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

     The format string is reused as often as necessary to satisfy the
     _a_r_g_u_m_e_n_t_s.  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:

           \\aa      Write a <bell> character.
           \\bb      Write a <backspace> character.
           \\cc      Ignore remaining characters in this string.
           \\ff      Write a <form-feed> character.
           \\nn      Write a <new-line> character.
           \\rr      Write a <carriage return> character.
           \\tt      Write a <tab> character.
           \\vv      Write a <vertical tab> character.
           \\''      Write a <single quote> character.
           \\\\      Write a backslash character.
           \\_n_u_m
           \\00_n_u_m   Write an 8-bit character whose ASCII value is the 1-, 2-,
                   or 3-digit octal number _n_u_m.

     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 cc, dd, and ss, for-
                     mats, this option has no effect.  For the oo formats the
                     precision of the number is increased to force the first
                     character of the output string to a zero.  For the xx (XX)
                     format, a non-zero result has the string 0x (0X)
                     prepended to it.  For ee, EE, ff, gg, and GG, 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 fol-
                     lows the decimal point).  For gg and GG formats, trailing
                     zeros are not removed from the result as they would oth-
                     erwise be;

             --       A minus sign `-' which specifies _l_e_f_t _a_d_j_u_s_t_m_e_n_t 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;

             00       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 _f_i_e_l_d _w_i_d_t_h; if the output
             string has fewer characters than the field width it will be
             blank-padded on the left (or right, if the left-adjustment indi-
             cator 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 _p_r_e_c_i_s_i_o_n which specifies the number of digits to appear
             after the decimal point, for ee and ff formats, or the maximum num-
             ber of characters 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
             ddiioouuxxXXffFFeeEEggGGaaAAccssbb).  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
             (ffFFeeEEggGGaaAA) may be prefixed by an LL 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 _a_r_g_u_m_e_n_t supplies the field width or precision.

     The format characters and their meanings are:

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

     ffFF          The _a_r_g_u_m_e_n_t 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 _N_a_N are printed as `inf' and `nan', respec-
                 tively.

     eeEE          The _a_r_g_u_m_e_n_t is printed in the style ee `[-_d_._d_d_d+-_d_d]' 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 _N_a_N are printed as `inf' and `nan',
                 respectively.

     ggGG          The _a_r_g_u_m_e_n_t is printed in style ff (FF) or in style ee (EE)
                 whichever gives full precision in minimum space.

     aaAA          The _a_r_g_u_m_e_n_t is printed in style `[-_h_._h_h_h+-p_d]' 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 _N_a_N are
                 printed as `inf' and `nan', respectively.

     cc           The first character of _a_r_g_u_m_e_n_t is printed.

     ss           Characters from the string _a_r_g_u_m_e_n_t are printed until the end
                 is reached or until the number of characters indicated by the
                 precision specification is reached; however if the precision
                 is 0 or missing, all characters in the string are printed.

     bb           As for ss, but interpret character escapes in backslash nota-
                 tion in the string _a_r_g_u_m_e_n_t.

     %%           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.

EEXXIITT SSTTAATTUUSS
     The pprriinnttff utility exits 0 on success, and >0 if an error occurs.

CCOOMMPPAATTIIBBIILLIITTYY
     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.

SSEEEE AALLSSOO
     echo(1), printf(3)

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

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

BBUUGGSS
     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 LL modifier may produce additional precision,
     depending on the hardware platform.)

     ANSI hexadecimal character constants were deliberately not provided.

     The escape sequence \000 is the string terminator.  When present in the
     argument for the bb 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).

     Parsing of - arguments is also somewhat different from printf(3), where
     unknown arguments are simply printed instead of being flagged as errors.

BSD                             April 14, 2005                             BSD
