printf format specifications quick reference

The printf man page is more like a specification than a quick reference.
Here is my quick reference for the "conversion specifications format"
aka the "format specification fields". Note this info is based on
the printf man page in man-pages-1.67-7 from the LDP (on Fedora Core 4)

%[flags][min field width][precision][length]conversion specifier
 -----  ---------------  ---------  ------ -------------------
  \             #,*        .#, .*     /             \
   \                                 /               \
  #,0,-,+, ,',I                 hh,h,l,ll,j,z,L    c,d,u,x,X,e,f,g,s,p,%
  -------------                 ---------------    -----------------------
  # | Alternate,                 hh | char,           c | unsigned char,
  0 | zero pad,                   h | short,          d | signed int,
  - | left align,                 l | long,           u | unsigned int,
  + | explicit + - sign,         ll | long long,      x | unsigned hex int,
    | space for + sign,           j | [u]intmax_t,    X | unsigned HEX int,
  ' | locale thousands grouping,  z | size_t,         e | [-]d.ddde±dd double,
  I | Use locale's alt digits     t | ptrdiff_t,      E | [-]d.dddE±dd double,
                                  L | long double,  ---------=====
  if no precision   => 6 decimal places            /  f | [-]d.ddd double,
  if precision = 0  => 0 decimal places      _____/   g | e|f as appropriate,
  if precision = #  => # decimal places               G | E|F as appropriate,
  if flag = #       => always show decimal point      s | string,
                                            ..............------
                                           /          p | pointer,
  if precision      => max field width    /           % | %

Examples of common combinations:

format	output
printf("%08X",32_bit_var);	0000ABCD
printf("%lu",32_bit_var);	43981
printf("%'d",32_bit_var);	43,981
printf("%10s","string");	string
printf("%*s",10,"string");	string
printf("%-10s","string");	string
printf("%-10.10s","truncateiftoolong");	truncateif

Note for the %'d one to work you must have already set your locale as in the following example:

#include 
#include 

int main(void)
{
   setlocale(LC_ALL,"");
   printf("%'Id\n",1234);
}

$ ./numtest
1,234

$ LANG=fa_IR.utf8 ./numtest
۱٬۲۳۴

For details on printing system types like off_t, and time_t and the C99 types like uint32_t etc. portably, please see here.