printf — Write formatted output

printf format [argument ...]

Purpose

printf writes the argument operands to standard output, formatted according to the format operand.

format is a format string composed of conversion specifications that convert and add the next argument to the output. format can contain backslash-escape sequences. These conversions are similar to those used by the ANSI C standard. Conversion specifications have the form: 
%[flag][width][precision][char]
where flag is one of the following:
-
Left-justifies the field; default is right justification.
+
Always prefixes a signed value with a sign (+ or -).
space
Reserves a character position at the start of the string for the minus sign (for negative numbers) or a space (for positive numbers). If both space and - appear as flags, the space flag is ignored.
#
Prefixes octal values with 0 and hexadecimal values with 0x or 0X. For floating-point values, this causes the decimal point always to be displayed even if no characters follow it.
0
Pads numeric values with leading zeros. If both 0 and - appear as flags, the 0 flag is ignored.

width is the minimum field width of the output field. If the converted value is shorter than the minimum width, printf pads it with spaces or zeros.

In a string, precision is the maximum number of bytes to be printed from the string; in a number, the precision is the number of digits to be printed to right of the decimal point in a floating-point value. width or precision can be specified as *, in which case the value is read from the next argument, which must be an integer. For example: 
printf "%*.*d\n" 20 10 200
is equivalent to: 
printf "%20.10d\n" 200
The conversion character char is one of the following:
d
Decimal integer.
i
Decimal integer.
o
Unsigned octal integer.
x,X
Unsigned hexadecimal integer.
u
Unsigned decimal integer.
f,F
Floating point.
e,E
Floating point (scientific notation).
g,G
The shorter of e and f (suppresses insignificant zeros).
c
Single character of an integer value; the first character of a string.
s
String.
b
A string that may contain a backslash-escape sequence. Valid escape sequences are those described in echo — Write arguments to standard output.
\0ddd
Where ddd is 0-to-3-digit octal number
\xdd
Where dd is a 0-to-2-digit hexadecimal number
\c
Indicates the first character of a string; number arguments are treated as strings.

When there are more arguments than positions in format, the format string is applied again to the remaining arguments. When there are fewer arguments than there are positions in the format string, printf fills the remaining positions with null strings (character fields) or zeros (numeric fields).

Localization

printf uses the following localization environment variables:
  • LANG
  • LC_ALL
  • LC_CTYPE
  • LC_MESSAGES
  • LC_NUMERIC
See Localization for more information.

Exit Values

Possible exit status values are:
0
Successful completion
>0
The number of failures due to any of the following:
  • Missing format specifications
  • Arguments supplied for a format string that does not accept them (that is, that has no %s)
  • Incorrect integer argument
  • Incorrect floating-point argument

Portability

POSIX.2, UNIX system V.

The %F format and the handling of * as a width or precision argument are extensions of the POSIX standard.

Related Commands

echo, print