strtime

GNU Date

Directive	Meaning
`%%`	a literal %
`%a`	locale’s abbreviated weekday name (e.g., Sun)
`%A`	locale’s full weekday name (e.g., Sunday)
`%b`	locale’s abbreviated month name (e.g., Jan)
`%B`	locale’s full month name (e.g., January)
`%c`	locale’s date and time (e.g., Thu Mar 3 23:05:25 2005)
`%C`	century; like %Y, except omit last two digits (e.g., 20)
`%d`	day of month (e.g., 01)
`%D`	date; same as %m/%d/%y
`%e`	day of month, space padded; same as %_d
`%F`	full date; like %+4Y-%m-%d
`%g`	last two digits of year of ISO week number (see %G)
`%G`	year of ISO week number (see %V); normally useful only with %V
`%h`	same as %b
`%H`	hour (00..23)
`%I`	hour (01..12)
`%j`	day of year (001..366)
`%k`	hour, space padded ( 0..23); same as %_H
`%l`	hour, space padded ( 1..12); same as %_I
`%m`	month (01..12)
`%M`	minute (00..59)
`%n`	a newline
`%N`	nanoseconds (000000000..999999999)
`%p`	locale’s equivalent of either AM or PM; blank if not known
`%P`	like %p, but lower case
`%q`	quarter of year (1..4)
`%r`	locale’s 12-hour clock time (e.g., 11:11:04 PM)
`%R`	24-hour hour and minute; same as %H:%M
`%s`	seconds since 1970-01-01 00:00:00 UTC
`%S`	second (00..60)
`%t`	a tab
`%T`	time; same as %H:%M:%S
`%u`	day of week (1..7); 1 is Monday
`%U`	week number of year, with Sunday as first day of week (00..53)
`%V`	ISO week number, with Monday as first day of week (01..53)
`%w`	day of week (0..6); 0 is Sunday
`%W`	week number of year, with Monday as first day of week (00..53)
`%x`	locale’s date representation (e.g., 12/31/99)
`%X`	locale’s time representation (e.g., 23:13:48)
`%y`	last two digits of year (00..99)
`%Y`	year
`%z`	+hhmm numeric time zone (e.g., -0400)
`%:z`	+hh:mm numeric time zone (e.g., -04:00)
`%::z`	+hh:mm:ss numeric time zone (e.g., -04:00:00)
`%:::z`	numeric time zone with : to necessary precision (e.g., -04, +05:30)
`%Z`	alphabetic time zone abbreviation (e.g., EDT)

By default, date pads numeric fields with zeroes. The following optional flags may follow %:

Directive	Meaning
`-`	(hyphen) do not pad the field
`_`	(underscore) pad with spaces
`0`	(zero) pad with zeros
`+`	pad with zeros, and put ‘+’ before future years with >4 digits
`^`	use upper case if possible
`#`	use opposite case if possible

Reference: GNU Date Man Page

Python

Directive	Meaning
`%a`	Weekday as locale’s abbreviated name.
`%A`	Weekday as locale’s full name.
`%w`	Weekday as a decimal number, where 0 is Sunday and 6 is Saturday.
`%d`	Day of the month as a zero-padded decimal number.
`%b`	Month as locale’s abbreviated name.
`%B`	Month as locale’s full name.
`%m`	Month as a zero-padded decimal number.
`%y`	Year without century as a zero-padded decimal number.
`%Y`	Year with century as a decimal number.
`%H`	Hour (24-hour clock) as a zero-padded decimal number.
`%I`	Hour (12-hour clock) as a zero-padded decimal number.
`%p`	Locale’s equivalent of either AM or PM.
`%M`	Minute as a zero-padded decimal number.
`%S`	Second as a zero-padded decimal number.
`%f`	Microsecond as a decimal number, zero-padded on the left.
`%z`	UTC offset in the form +HHMM or -HHMM (empty string if the the object is naive).
`%Z`	Time zone name (empty string if the object is naive).
`%j`	Day of the year as a zero-padded decimal number.
`%U`	Week number of the year (Sunday as the first day of the week) as a zero padded decimal number. All days in a new year preceding the first Sunday are considered to be in week 0.
`%W`	Week number of the year (Monday as the first day of the week) as a decimal number. All days in a new year preceding the first Monday are considered to be in week 0.
`%c`	Locale’s appropriate date and time representation.
`%x`	Locale’s appropriate date representation.
`%X`	Locale’s appropriate time representation.
`%%`	A literal ‘%’ character.

Reference: Python Datetime Docs

GoLang

Specify your desired format using Mon Jan 2 15:04:05 -0700 MST 2006.

Directive	Meaning
`Mon`	Weekday as locale’s abbreviated name.
`Monday`	Weekday as locale’s full name.
`Jan`	Month as locale’s abbreviated name.
`January`	Month as locale’s full name.
`1`	Month as decimal number.
`01`	Month as a zero-padded decimal number.
`2`	Day of the month as decimal number.
`02`	Day of the month as a zero-padded decimal number.
`15`	Hour (24-hour clock) as a zero-padded decimal number.
`3`	Hour (12-hour clock) as a decimal number.
`03`	Hour (12-hour clock) as a zero-padded decimal number.
`pm`	Locale’s equivalent of either am or pm.
`PM`	Locale’s equivalent of either AM or PM.
`4` `04`	Minute as a zero-padded decimal number.
`5` `05`	Second as a zero-padded decimal number.
`06`	Year without century as a zero-padded decimal number.
`2006`	Year with century as a decimal number.
`-07`	UTC offset in the form +HH or -HH (empty string if the the object is naive).
`-0700`	UTC offset in the form +HHMM or -HHMM (empty string if the the object is naive).
`MST`	Time zone name (empty string if the object is naive).

Reference: Time.Format GoDoc