printf
respects locale, may have to set LC_NUMERIC=C to get internationally agreed
behaviour.
format placeholder syntax
%[parameter][flags][width][.precision][length]type
parameter
n$, specify parameter position, missing in shells and gnu coreutils printf.
flags
-: left align+: sign positive numbers as well : don't sign positive numbers but prepend space0: in conjunction w/ width, pad w/ zeroes instead of spaces#: g: include trailing zeroes, e, f, g: include decimal point,
o, x: prepend w/ 0 or 0x
width
minimum width of output. allows dynamic value w/ *.
precision
maximum limit, for floating point round digitsafter decimal point, for string
truncate. allows dynamic value w/ *. following examples behave same.
printf '%.2f' 42.239
printf '%.*f' 2 42.239
length
can be omitted.
type
d, i: signed int as decimal, behave sameu: unsigned int as decimalf, F: double as fixed point, uses lower- or uppercase on inf and NaNe, E: exponent notation, 1 == 1.000000e+00, 10 == 1.000000e+01g, G: shorten, f or e whichever applies best, omit traling zeroesx, X: unsigned int as hex, use lower- or uppercaseo: unsigned int as octals: stringc: chara, A: double in hex