Perl Pocket Reference, 4th Edition

Chapter 27. Formatted Printing

printf and sprintf format a list of values according to a format string that may use the following conversions:

%%	A percent sign.
%b	An unsigned number (binary).
%c	The character corresponding to the ordinal value.
%d	A signed integer.
%e	A floating-point number (scientific notation).
%f	A floating-point number (fixed decimal notation).
%g	A floating-point number (%e or %f notation).
%i	A synonym for %d.
%n	The number of characters formatted so far is stored into the corresponding variable in the parameter list.
%o	An unsigned integer, in octal.
%p	A pointer (address in hexadecimal).
%s	A string.
%u	An unsigned integer (decimal).
%x	An unsigned integer (hexadecimal).
%D	An obsolete synonym for %ld.
%E	Like %e, but using an uppercase E.
%F	An obsolete synonym for %f.
%G	Like %g, but with an uppercase E (if applicable).
%O	An obsolete synonym for %lo.
%U	An obsolete synonym for %lu.
%X	Like %x, but using uppercase letters.

The following flags can be put between the % and the conversion letter:

space	Prefix a positive number with a space.
+	Prefix a positive number with a plus sign.
−	Left-align within the field.
0	Use zeroes instead of spaces to right-align.
#	With o, b, x, and X: prefix a nonzero number with 0, 0b, 0x, or 0X.
number	Minimum field width.
.number	For a floating-point number, the number of digits after the decimal point. For a string, the maximum length. For an integer, the minimum width.
h	Interpret integer as short or unsigned short according to the C type.
l	Interpret integer as long or unsigned ...