Oh my. There are the formatting characters.

When I was hunting for ruby date formatting characters I really should have searched for Time.strftime directives:

%a The abbreviated weekday name (``Sun'')

%A The full weekday name (``Sunday'')

%b The abbreviated month name (``Jan'')

%B The full month name (``January'')

%c The preferred local date and time representation

%d Day of the month (01..31)

%H Hour of the day, 24-hour clock (00..23)

%I Hour of the day, 12-hour clock (01..12)

%j Day of the year (001..366)

%m Month of the year (01..12)

%M Minute of the hour (00..59)

%p Meridian indicator (``AM'' or ``PM'')

%S Second of the minute (00..60)

%U Week number of the current year, starting with the first Sunday as the first day of the first week (00..53)

%W Week number of the current year, starting with the first Monday as the first day of the first week (00..53)

%w Day of the week (Sunday is 0, 0..6)

%x Preferred representation for the date alone, no time

%X Preferred representation for the time alone, no date

%y Year without a century (00..99)

%Y Year with century

%Z Time zone name

%% Literal ``%'' character