https://www.erlang.org/doc/apps/stdlib/io.html

The general format for an io:format control sequence in Erlang is ~F.P.PadModC.
The character C determines the type of specifier, while F, P, Pad, and Mod are
optional modifiers for field width, precision, padding, and other settings.

Here is a list of the available control sequences (specifiers):

~: Prints a literal ~ character.

c: The argument (an integer ASCII code) is printed as a character. The precision
determines the number of times it's printed.

f: The argument (a float) is printed as [-]ddd.ddd. The precision determines the
number of digits after the decimal point (default is 6).

e: The argument (a float) is printed in scientific notation [-]d.ddde+-ddd. The
precision is the number of digits after the decimal point (default is 6).

g: The argument (a float) is printed using the shortest form of ~f or ~e. The
precision determines the number of significant digits (default is 6).

s: The argument (a string/character_list or atom) is printed without quotes. It
can be truncated by precision.

w: The argument is printed with the standard Erlang term syntax, similar to
erlang:term_to_io_list/1.

p: Similar to ~w, but formats the output over multiple lines with sensible
indentation if the term is long, which is useful for complex data structures.

W: Similar to ~w, but takes an extra integer argument from the data list that
specifies the maximum depth to which terms are printed.

P: Similar to ~p, but takes an extra integer argument for the maximum depth,
enabling depth-limited pretty printing.

B: The argument (an integer) is printed in a specified base (2-36, default is
10). The field width and precision can control padding and minimum digits.

b: Similar to ~B, but uses lowercase letters for bases > 10.

X: Similar to ~B, but takes an extra argument for a prefix to insert before the
number (after a leading dash, if any).

x: Similar to ~X, but uses lowercase letters.

#: Similar to ~B, but prints the number with an Erlang-style base prefix (e.g.,
 16#ffff).

+: Similar to ~#, but uses lowercase letters.

n: Writes a newline character. Takes no arguments.

i: Ignores the next argument in the data list. Useful for commenting out
arguments in the format string.