Date Time Formats in Ruby on Rails

Different types of Date Time Format with their meaning:

  %a - The abbreviated weekday name (``Sun'') 
  %b - The abbreviated month name (``Jan'')
  %c - The preferred local date and time representation
  %d - Day of the month (01..31)
  %e - Day of the month without a leading zero (1..31)
  %j - Day of the year (001..366)
  %m - Month of the year (01..12)
  %p - Meridian indicator (``AM''  or  ``PM'')
  %w - Day of the week (Sunday is 0, 0..6)
  %x - Preferred representation for the date alone, no time
  %y - Year without a century (00..99)

  %A - The  full  weekday  name (``Sunday'')
  %B - The  full  month  name (``January'')
  %H - Hour of the day, 24-hour clock (00..23)
  %I - Hour of the day, 12-hour clock (01..12) 
  %M - Minute of the hour (00..59)
  %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)
 
  %X - Preferred representation for the time alone, no date
  %Y - Year with century
  %Z - Time zone name
  %% - Literal ``%'' character

Examples to use them:

   t = Time.now                       #=> "Wed Feb 16 17:04:52 +0530 2011"
   t.strftime("%d-%m-%Y")                         #=> "16-02-2011"
   t.strftime("at %I:%M%p")                        #=> "at 05:07PM"
   t.strftime("%m/%d/%Y %H:%M:%S")     #=> "02/16/2011 17:08:40"