The date command uses the

Help information for the date command
[Email protected] source]# date--help
Usage: date [options] ... [+ format]
Or: Date [-u|--utc|--universal] [MMDDHHMM[[CC]YY][.SS]]
Displays the current time in the given format, or sets the system date.

-D,--date= string displays the time described by the specified string, not the current time
-F,--file= date file similar to--date, read-in time description by line from the date file
-R,--reference= file shows the last modified time for file specified file
-R,--rfc-2822 output date and time in RFC 2822 format
Example: August 7, 2006, Monday 12:34:56-0600
--rfc-3339=timespec outputs the date and time in RFC 3339 format.
timespec= ' Date ', ' seconds ', or ' ns '
Represents the display precision of a date and time.
The date and time units are separated by a single space:
2006-08-07 12:34:56-06:00
-S,--set= string sets the specified string to separate the time
-U,--UTC,--universal output or set Coordinated Universal Time
--HELP Display this help message and exit
--version display version information and exit

The given format controls the output, and the sequence is interpreted as follows:

Percent of a text%
%a of the current locale (ex: day, for Sunday)
%A the full name of the current locale (for example: Sunday)
%b the month name of the current locale (for example: one, for January)
%B the full name of the current locale (for example: January)
The date and time of the current locale of%c (for example: March 3, 2005 Thursday 23:05:25)
%c century; For example,%Y, typically omitting the last two digits of the current year (for example: 20)
%d date by month (ex: 01)
%d Date by month; equal to%m/%d/%y
%e date by month, add a space, equal to%_d
%F full date format, equivalent to%y-%m-%d
%g last two bits of the ISO-8601 format year (see%G)
%G ISO-8601 format year (see%V), typically used only with%V
%h equals%b.
%H hours (00-23)
%I Hours (00-12)
%m Month (01-12)
%M points (00-59)
%n line break
%N nanosecond (000000000-999999999)
%p "Morning" or "afternoon" under current locale, output empty when unknown
%P is similar to%P, but outputs lowercase letters
%r 12-hour clock time at current locale (e.g. 11:11:04 pm)
%R 24 hours of time and minutes, equivalent to%h:%m
%s number of seconds since 1970-01-01 00:00:00 UTC time
%s seconds (00-60)
%t Output Tab tab
%T time, equal to%h:%m:%s
%u week, 1 stands for Monday
%u week of the year, with Sunday as the first day of the Week (00-53)
%V ISO-8601 Format Specification for the week of the year, with Monday as the first day of the Week (01-53)
%w Day of the Week (0-6), 0 for Monday
%W Week of the year, with Monday as the first day of every week (00-53)
Date description under the current locale of%x (for example: 12/31/99)
Time description Under current locale of%x (e.g. 23:13:48)
%y year last two digits (00-99)
%Y year
%z +HHMM Digital Time zone (for example,-0400)
%:z +hh:mm Digital Time zone (for example, -04:00)
%::z +HH:MM:SS Digital Time zone (for example, -04:00:00)
%:::z Digital time zone with the necessary precision (for example, -04,+05:30)
%Z time zone abbreviations by alphabet (for example, EDT)

By default, the numeric area of a date is populated with 0.
The following optional tags can be followed by "%" after:

-(hyphen) does not populate the field
_ (underline) fills with spaces
0 (number 0) with 0 padding
^ If possible, use uppercase letters
# if possible, use the opposite case

Also allows an optional field width to be specified after any tag, which is a decimal number.

As an optional cosmetic declaration, it can be E, using the Local environment association if possible
Representation, or O, where possible, using a numeric symbol associated with the local environment.

The date command uses the