date(1)
NAME
date - write the date and time
SYNOPSIS
/usr/bin/date [-u] [ +format]
/usr/bin/date [ -a [-]sss.fff]
/usr/bin/date [-u] [ [mmdd] HHMM | mmddHHMM [cc] yy] [.SS]
/usr/xpg4/bin/date [-u] [ +format]
/usr/xpg4/bin/date [ -a [-]sss.fff]
/usr/xpg4/bin/date [-u] [ [mmdd] HHMM | mmddHHMM [cc] yy]
[.SS]
DESCRIPTION
The date utility writes the date and time to standard output
or attempts to set the system date and time. By default, the
current date and time will be written.
Specifications of native language translations of month and
weekday names are supported. The month and weekday names
used for a language are based on the locale specified by the
environment variable LC_TIME. See environ(5).
The following is the default form for the "C" locale:
%a %b %e %T %Z %Y
For example,
Fri Dec 23 10:10:42 EST 1988
OPTIONS
The following options are supported:
-a [-]sss.fff
Slowly adjust the time by sss.fff seconds (fff
represents fractions of a second). This adjustment can
be positive or negative. The system's clock will be
sped up or slowed down until it has drifted by the
number of seconds specified. Only the super-user may
adjust the time.
-u Display (or set) the date in Greenwich Mean Time
(GMT-universal time), bypassing the normal conversion
to (or from) local time.
OPERANDS
The following operands are supported:
+format
If the argument begins with +, the output of date is
the result of passing format and the current time to
strftime(). date uses the conversion specifications
listed on the strftime(3C) manual page, with the
conversion specification for %C determined by whether
/usr/bin/date or /usr/xpg4/bin/date is used:
/usr/bin/date
Locale's date and time representation. This is the
default output for date.
/usr/xpg4/bin/date
Century (a year divided by 100 and truncated to an
integer) as a decimal number [00-99].
The string is always terminated with a NEWLINE. An argument
containing blanks must be quoted; see the EXAMPLES section.
mm Month number
dd Day number in the month
HH Hour number (24 hour system)
MM Minute number
SS Second number
cc Century (a year divided by 100 and truncated to an
integer) as a decimal number [00-99]. For example, cc
is 19 for the year 1988 and 20 for the year 2007.
yy Last two digits of the year number. If century (cc) is
not specified, then values in the range 69-99 shall
refer to years 1969 to 1999 inclusive, and values in
the range 00-68 shall refer to years 2000 to 2068,
inclusive.
The month, day, year number, and century may be omitted; the
current values are applied as defaults. For example, the
following entry:
example% date 10080045
sets the date to Oct 8, 12:45 a.m. The current year is the
default because no year is supplied. The system operates in
GMT. date takes care of the conversion to and from local
standard and daylight time. Only the super-user may change
the date. After successfully setting the date and time, date
displays the new date according to the default format. The
date command uses TZ to determine the correct time zone
information; see environ(5).
EXAMPLES
Example 1: Generating output
The command
example% date '+DATE: %m/%d/%y%nTIME:%H:%M:%S'
generates as output
DATE: 08/01/76
TIME: 14:45:05
Example 2: Setting the current time
The command
example# date 1234.56
sets the current time to 12:34:56.
Example 3: Setting another time and date in Greenwich Mean
Time
The command
example# date -u 010100302000
sets the date to January 1st, 12:30 am, 2000, which will be
displayed as
Thu Jan 01 00:30:00 GMT 2000
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment
variables that affect the execution of date: LANG, LC_ALL,
LC_CTYPE, LC_TIME, LC_MESSAGES, and NLSPATH.
TZ Determine the timezone in which the time and date are
written, unless the -u option is specified. If the TZ
variable is not set and the -u is not specified, the
system default timezone is used.
EXIT STATUS
The following exit values are returned:
0 Successful completion.
>0 An error occurred.
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
/usr/bin/date
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWcsu |
|_____________________________|_____________________________|
| CSI | enabled |
|_____________________________|_____________________________|
/usr/xpg4/bin/date
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Availability | SUNWxcu4 |
|_____________________________|_____________________________|
| CSI | enabled |
|_____________________________|_____________________________|
| Interface Stability | Standard |
|_____________________________|_____________________________|
SEE ALSO
strftime(3C), attributes(5), environ(5), standards(5)
DIAGNOSTICS
no permission
You are not the super-user and you tried to change the
date.
bad conversion
The date set is syntactically incorrect.
NOTES
If you attempt to set the current date to one of the dates
that the standard and alternate time zones change (for exam-
ple, the date that daylight time is starting or ending), and
you attempt to set the time to a time in the interval
between the end of standard time and the beginning of the
alternate time (or the end of the alternate time and the
beginning of standard time), the results are unpredictable.
Using the date command from within windowing environments to
change the date can lead to unpredictable results and is
unsafe. It may also be unsafe in the multi-user mode, that
is, outside of a windowing system, if the date is changed
rapidly back and forth. The recommended method of changing
the date is 'date -a'.
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