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HP-UX 11i Version 3: February 2007

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printf — format and print arguments


printf format [arg ...]


printf writes formatted arguments to the standard output. The arg arguments are formatted under control of the format operand.

format is a character string patterned after the formatting conventions of printf() (see printf(3S)), and contains the following types of objects:


Characters that are not escape sequences or conversion specifications (as described below) are copied to standard output.

escape sequences

These are interpreted as non-graphic characters:










carriage return




vertical tab


single quote character




the 8-bit character whose ASCII code is the 1-, 2-, 3-, or 4-digit octal number n, whose first character must be a zero.

conversion specification

Specifies the output format of each argument (see below).

Arguments following format are interpreted as strings if the corresponding format is either c or s; otherwise they are treated as constants.

Conversion Specifications

Each conversion specification is introduced by the percent character %. After the % character, the following can appear in the sequence indicated:


Zero or more flags, in any order, which modify the meaning of the conversion specification. The flag characters 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 -.


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 flag and + flag both appear, the space flag is ignored.


The value is to be converted to an "alternate form". For c, d, i, u, and s conversions, this flag has no effect. 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. 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, contrary to usual behavior.

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, - has been given) to the field width.


The precision specifies the minimum number of digits to appear for the d, o, i, u, x, or X conversions (the field is padded with leading zeros), the number of digits to appear after the radix character for the e and f conversions, the maximum number of significant digits for the g conversion, or the maximum number of bytes to be printed 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 a zero.

conversion characters

A conversion character indicates the type of conversion to be applied:




The integer argument is printed a signed decimal (d or i), unsigned octal (o), unsigned decimal (u), or unsigned hexadecimal notation (x and X). The x conversion uses the numbers and letters 0123456789abcdef, and the X conversion uses the numbers and letters 0123456789ABCDEF. The precision component 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 zeroes. The default precision is 1. The result of converting a zero value with a precision of 0 is no characters.


The floating-point number argument is printed in decimal notation in the style [-]dddrddd , where the number of digits after the radix character, r, is equal to the precision specification. If the precision is omitted from the argument, six digits are output; if the precision is explicitly 0, no radix appears.


The floating-point-number argument is printed in the style [-]drddddd , where there is one digit before the radix character, and the number of digits after it is equal to the precision. When the precision is missing, six digits are produced; if the precision is 0, no radix character appears. The E conversion character produces a number with E introducing the exponent instead of e. The exponent always contains at least two digits. However, if the value to be printed requires an exponent greater than two digits, additional exponent digits are printed as necessary.


The floating-point-number argument is printed in style f or e (or int 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 e is used only if the exponent resulting from the conversion is less than -h or greater than or equal to the precision. Trailing zeros are remove from the result. A radix character appears only if it is followed by a digit.


The first byte of the argument is printed.


The argument is taken to be a string, and characters from the string are printed 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 interpreted as infinite and all characters up to the end of the string are printed.


Print a % character; no argument is converted.


Similar to the s conversion specifier, except that the string can contain backslash-escape sequences which are then converted to the characters they represent. \c will cause printf to ignore any remaining characters in the string operand containing it, any remaining string operands and any additional characters in the format operand.

In no case does a nonexistent 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.


Environment Variables

LC_CTYPE determines the interpretation of arg as single and/or multi-byte characters.

LC_MESSAGES determines the language in which messages are displayed.

If LC_CTYPE or LC_MESSAGES is not specified in the environment or is set to the empty string, the value of LANG is used as a default for each unspecified or empty variable. If LANG is not specified or is set to the empty string, a default of "C" (see lang(5)) is used instead of LANG.

If any internationalization variable contains an invalid setting, printf behaves as if all internationalization variables are set to "C". See environ(5).

International Code Set Support

Single and multi-byte character code sets are supported.


printf exits with one of the following values:


Successful completion.


Errors occurred; the exit value is increased by one for each error that occurred up to a maximum of 255.


If an argument cannot be converted into a form suitable for the corresponding conversion specification, or for any other reason cannot be correctly printed, a diagnostic message is printed to standard error, the argument is output as a string form as it was given on the command line, and the exit value is incremented.


The following command prints the number 123 in octal, hexadecimal and floating point formats in their alternate form

printf "%#o, %#x, %#X, %#f, %#g, %#e\n" 123 123 123 123 123 123

resulting in the following output

0173, 0x7b, 0X7B, 123.000000, 123.000, 1.230000e+02

Print the outputs with their corresponding field widths and precision:

printf "%.6d, %10.6d, %.6f, %.6e, %.6s\n" 123 123 1.23 123.4 MoreThanSix

resulting in the following output

000123, 000123, 1.230000, 1.234000e+02, MoreTh


printf: XPG4, POSIX.2

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