The A descriptor is used for strings. The number of characters in the output
(the field width) is equal to the length of the string. The field width w
can be prescribed by using the form Aw. For example A20 is used for a
string in a field width of 20 characters. If the string has more than w characters
it is truncated. If it has fewer that w characters, it is padded out
with leading spaces.