illumos: manual page: date.1

DATE(1) User Commands DATE(1)

NAME

date - write the date and time

SYNOPSIS

/usr/bin/date [-u] [-r seconds | filename] [-R] [+format]

/usr/bin/date [-a [-]sss.fff]

/usr/bin/date [-u] [ [mmdd] HHMM | mmddHHMM [cc] yy] [.SS]

/usr/xpg4/bin/date [-u] [-r seconds | filename] [-R] [+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 is
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(7).

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 is sped up or slowed down until it
has drifted by the number of seconds specified.
Only the super-user may adjust the time.

-r seconds
Rather than using the current time, obtain the
time based on seconds. seconds will be treated as
time since the UNIX Epoch (00:00:00 UTC, January
1, 1970).

-r filename
Rather than using the current time, obtain the
time based on the modification time of filename.

-R
Change the default format to the format used for
mail message headers (similar to RFC 822 format).
The default format becomes

%a, %d %h %Y %H:%M:%S %z

-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].

In addition, the nonstandard conversion specification %N is
also supported, and is converted to the zero-padded number of
nanoseconds since the last second. Note that the actual
resolution of this number is limited to the resolution of the
system's CLOCK_REALTIME clock. See clock_gettime(3C).

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(7).

EXAMPLES

Example 1: Generating Output

The following 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 following command sets the current time to 12:34:56:

example# date 1234.56

Example 3: Setting Another Time and Date in Greenwich Mean Time

The following command sets the date to January 1st, 12:30 am, 2000:

example# date -u 010100302000

This is displayed as:

Thu Jan 01 00:30:00 GMT 2000

ENVIRONMENT VARIABLES

See environ(7) 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

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 example, 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 can 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'.

Setting the system time or allowing the system time to progress beyond
03:14:07 UTC Jan 19, 2038 is not supported on Solaris.

December 6, 2017 DATE(1)