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
See
attributes(7) for descriptions of the following attributes:
/usr/bin/date +---------------+-----------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------+
|CSI | enabled |
+---------------+-----------------+
/usr/xpg4/bin/date +--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|CSI | enabled |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
SEE ALSO
strftime(3C),
attributes(7),
environ(7),
standards(7)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)