1.definition
date - print or set the system date and time
2.SYNOPSIS
2.1 Display the current time in the given FORMAT.
date []... [+FORMAT]
FORMAT : refers to formatting symbols
You can look it up in the man manual
2.2 Set the system date.
date [MMDDhhmm[[CC]YY][.ss]]
MM : refers to month
DD : refers to day
hh : refers to hours
mm : refers to minutes
YY : refers to two-digit years
CCYY : refers to four-digit years
.ss : refers to seconds
e.g : Set the time to 17:01 am 21 seconds on August 15, 2015
# date 0815170115.21