ruby.txt

Date Time Format
================
 %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

   t = Time.now
   t.strftime("Printed on %m/%d/%Y")   #=> "Printed on 11/02/2011"
   t.strftime("at %I:%M%p")            #=> "at 12:56AM"