Date - print or set the system date and time

date [OPTION]... [+FORMAT]

date
Tue Sep 10 11:09:49 +07 2019

date -u
Tue Sep 10 04:10:54 UTC 2019

date --date="string"
date --date="last month"
date --date="last year"

date +%[format-option]
date +%D
09/10/19

%D: Display date as mm/dd/yy.       
%d: Display the day of the month (01 to 31).       
%a: Displays the abbreviated name for weekdays (Sun to Sat).
%A: Displays full weekdays (Sunday to Saturday).
%h: Displays abbreviated month name (Jan to Dec).
%b: Displays abbreviated month name (Jan to Dec).
%B: Displays full month name(January to December).
%m: Displays the month of year (01 to 12).
%y: Displays last two digits of the year(00 to 99).
%Y: Display four-digit year. 
%T: Display the time in 24 hour format as HH:MM:SS.
%H: Display the hour.
%M: Display the minute.
%S: Display the seconds.