because formatting times should be easy, like ruby's strftime
strftime:f(now(), "Printed on %m/%d/%Y"). %=> "Printed on 11/19/2007"
strftime:f(now(), "at %I:%M%p"). %=> "at 08:37AM"
strftime:f(now(), "at %I:%M%p", universal). %=> "at 02:37PM"
strftime:f(now(), "%D-%T.%N"). %=> "11/19/2007-08:38:02.445443"
strftime:f({epoch, os:system_time(1)},"%a, %d-%b-%Y %H:%M:%S GMT", universal).
strftime:f/2 uses system local time
strftime:f/3 allows you to specify 'local' or 'universal' as third argument.
strftime:f(now(), FormatString)
%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- Century (20 in 2009)%d- Day of the month (01..31)%D- Date (%m/%d/%y)%e- Day of the month, blank-padded ( 1..31)%F- Equivalent to %Y-%m-%d (the ISO 8601 date format)%h- Equivalent to %b%H- Hour of the day, 24-hour clock (00..23)%I- Hour of the day, 12-hour clock (01..12)%k- hour, 24-hour clock, blank-padded ( 0..23)%l- hour, 12-hour clock, blank-padded ( 0..12)%L- Millisecond of the second (000..999)%m- Month of the year (01..12)%M- Minute of the hour (00..59)%N- Fractional seconds digits%p- Meridian indicator ('AM' or 'PM')%P- Meridian indicator ('am' or 'pm')%r- time, 12-hour (same as %I:%M:%S %p)%R- time, 24-hour (%H:%M)%s- Number of seconds since 1970-01-01 00:00:00 UTC.%S- Second of the minute (00..60)%T- time, 24-hour (%H:%M:%S)%u- Day of the week as a decimal, Monday being 1. (1..7)%v- VMS date (%e-%b-%Y)%w- Day of the week (Sunday is 0, 0..6)%y- Year without a century (00..99)%Y- Year with century%%- Literal '%' character