date - Displays or sets the date
Without Superuser Authority - Displays the Date
date [-u] [+field_descriptor ...]
With Superuser Authority - Sets the Date [Toc] [Back]
date [-nu] [MMddhhmm.ssyy | alternate_date_format]
[+field_descriptor ...]
Using XCU5.0 - Sets or Displays the Date [Toc] [Back]
date [-u] mmddHHMM[yy]
date [-u] [+field_descriptor ...]
Using the Century Field - Sets the Date [Toc] [Back]
date mmddHHMM[[cc]yy] [.ss]
date [[cc]yy]mmddHHMM[.ss]
date mmddHHMM[.ss[[cc]yy]]
Interfaces documented on this reference page conform to
industry standards as follows:
date: XCU5.0
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
[Tru64 UNIX] Does not set the time globally on all
machines in a local area network that have their clocks
synchronized (superuser only). Performs operations as if
the TZ environment variable was set to the string GMT0.
Otherwise, date uses the time zone indicated by the TZ
environment variable or the system default if that variable
is not set.
The date command displays the date and, with superuser
authority, sets the system date. The date command has been
enhanced to support setting the system date past the year
1999, thus providing customers with the ability to begin
testing their software for potential century rollover
problems.
Displaying the Date [Toc] [Back]
The date command writes the current date and time to standard
output if called with no options or with a option
list that begins with a + (plus sign).
If you follow date with a + (plus sign) and a field
descriptor, you can control the output of the command.
You must precede each field descriptor with a % (percent
sign). The system replaces the field descriptor with the
specified value. Enter a literal % as %%. The date command
copies any other characters to standard output without
change. The date command always ends the string with a
newline character. Output fields are fixed size (zero
padded if necessary).
[Tru64 UNIX] The date command prints out a usage message
on any unrecognized options or input.
Field Descriptors [Toc] [Back]
Displays the locale's abbreviated weekday name (Sun to Sat
or the non-English equivalent). Displays the locale's
full weekday name. Displays the locale's abbreviated
month name. Displays the locale's full month name. Displays
the locale's appropriate time and date representation.
Displays the locale's century (the year divided by
100 and truncated to an integer) as a decimal number (00
to 99). Displays the day of month as a decimal number (01
to 31). Displays the date in the format mm/dd/yy independent
of the value specified by the LC_TIME environment
variable, if defined. Displays the day of the month as a
decimal number (1 to 31 in a 2-digit field with leading
space fill). Specifies the locale's alternative date and
time representation. Specifies the name of the base year
(period) in the locale's alternative representation.
Specifies the locale's alternative date representation.
Specifies the locale's alternative time representation.
Specifies the offset from %EC (year only) in the locale's
alternative representation. Specifies the full alternative
year representation. A synonym for %b. Displays the
hour as a decimal number (00 to 23). Displays the hour as
a decimal number (01 to 12). Displays the day of year as
a decimal number (001 to 366). Displays the month of year
as a decimal number (01 to 12). Displays the minute as a
decimal number (00 to 59). Inserts a newline character.
[Tru64 UNIX] Represents the alternative era name. [Tru64
UNIX] Represents the alternative era year. Specifies the
day of the month using the locale's alternative numeric
symbols. Specifies the day of the month using the
locale's alternative numeric symbols. Specifies the hour
(24-hour clock) using the locale's alternative numeric
symbols. Specifies the hour (12-hour clock) using the
locale's alternative numeric symbols. Specifies the month
using the locale's alternative numeric symbols. Specifies
the minutes using the locale's alternative numeric symbols.
Specifies the seconds using the locale's alternative
numeric symbols. Specifies the weekday as a number
in the locale's alternative representation (Monday=1).
Specifies the week number of the year (Sunday as the first
day of the week) using the locale's alternative numeric
symbols. Specifies the weekday as a number in the
locale's alternative representation (Sunday = 0). Specifies
the week number of the year (Monday as the first day
of the week) using the locale's alternative numeric symbols.
Specifies the year (offset from %C) in alternative
representation. Displays the locale's equivalent of
either AM or PM. Displays the time (12-hour clock) using
AM/PM notation (or the non-English equivalent) in the format
hh:mm:ss AM or hh:mm:ss PM. Displays the second as a
decimal number (00 to 61). Inserts a tab character. Displays
the time in 24-hour clock format as hh:mm:ss (the
default), or as specified by the LC_TIME environment variable,
if defined. Displays the weekday as a decimal number
[1,7], with 1 representing Monday. Displays the week
number of the year (Sunday is the first day of the week)
as a decimal number (00 to 53). All days in a new year
preceding the first Sunday are considered to be in week 0.
Displays the week number of the year (Monday as the first
day of the week) as a decimal number (01 to 53). If the
week containing January 1 has four or more days in the new
year, then it is considered week 1; otherwise, it is week
53 of the previous year, and the next week is week 1.
Displays the day of the week as a decimal number (Sunday
= 0). Displays the week number of the year (Monday is
the first day of the week) as a decimal number (00 to 53).
All days in a new year preceding the first Monday are considered
to be in week 0. Displays the locale's appropriate
date representation. Displays the locale's appropriate
time representation. Displays the last two numbers of
the year as a decimal number (00 to 99). Displays the
full year as a decimal number. Displays the time zone
name, or no characters if the time zone cannot be determined.
Inserts a % character.
Setting the Date [Toc] [Back]
Only a user operating with superuser authority can change
the date and time.
The default input format for setting the date is mmddHHMM[[cc]yy][.ss]
where: mm is the month number (01=January).
dd is the number of the day in the month. HH is
the hour in the day (using a 24-hour clock). MM is the
number of minutes. cc is the first two digits of the
year. yy is the last two digits of the year. If this
field is omitted, the current year is used. ss is the
number of seconds.
The LC_TIME variable, if defined, controls the ordering of
the day (dd) and month (mm) numbers in these formats. The
default order is the month (mm) followed by the day (dd).
Each of the formats allows you to specify the century
(first two digits of the year). This century field (cc)
is optional to ensure that input formats previously
accepted by the date command are still supported.
Currently, theXCU5.0 format does not have a century field.
This is consistent with current X/Open specifications
regarding the date command. The century field will be
added to this format in a future release of the operating
system once this new field is officially supported in
future revisions of X/Open's UNIX specification.
[Tru64 UNIX] Reset the date in single-user mode only.
Changing the date in multiuser mode could cause the creation
and modifications dates for user files to be inconsistent.
[Tru64 UNIX] To change the year, the system disk must be
updated with the new year information. To change the year,
in single-user mode enter the following command after you
enter a date containing a new year: mount -u /
The mount -u / command writes the new year into the
superblock on the system disk. The root file system is now
mounted read/write.
Handling of Two-Digit Year Input [Toc] [Back]
When the year is specified using two digits (as in the
XCU5.0 format or when the [cc] field is omitted ), the
century is determined in the following manner: if the
specified two-digit year is between 69 and 99 inclusive,
the 20th century is assumed (that is, 19yy); otherwise,
the 21st century is assumed (that is, 20yy).
This algorithm for determining the century is consistent
with current drafts of forthcoming X/Open UNIX specifications
regarding two-digit year handling in various system
interfaces and commands, including the date command. This
algorithm is based on the standard UNIX epoch (12:00:00 AM
Jan 1, 1970 UTC), minus one year to account for different
time zones. Internal UNIX time handling is based on the
number of seconds in this epoch.
Handling of Ambiguous Input [Toc] [Back]
If the input string is ambiguous, that is, if the format
cannot be conclusively determined from the data, the date
command will issue a warning to stderr and assume the mmddHHMM[[cc]yy][.ss]
format. To avoid ambiguous input, use
one of our formats and specify the [cc] field.
To display current date and time, enter: date
Depending on your current locale, the output might
look like one of the following: Thu Apr 16
13:21:30 EDT 1998
jeu 16 avr 17:21:30 CUT 1998
tor 16 apr 17:21:30 CUT 1998
The first output line is for an American English
locale, the second is for a French locale, and the
third is for a Danish locale. To set the date and
time, enter: date 02171425.45
This sets the date and time to 14:25:45 (45 seconds
after 2:25 p.m.) February 17 of the current year.
To display the date and time in a specified format,
enter: date +"%r %d %h %y (%a)"
This displays the date (assume current year is
1993) shown in Example 2 as: 02:25:45 PM 17 Feb
99 (Fri)
Do not set the date in multi-user mode.
Year 2000 Examples [Toc] [Back]
To set the date to 09:34:00 AM Jan 7, 2000: Using the mmddHHMM[[cc]yy][.ss]
format: date 010709342000 date
0107093400.00 date 010709342000.00 Using the [[cc]yy]mmddHHMM[.ss]
format: date 0001070934 date 200001070934 date
200001070934.00 Using the mmddHHMM[.ss[[cc]yy]] format:
date 01070934.0000 date 01070934.002000 Using the mmddHHMM[yy]
format: date 0107093400 An example of ambiguous
input: XCU5.0 date 0101010000
This input could be recognized as one of the following
formats:
mmddHHMM[[cc]yy][.ss] meaning 01:00:00 AM Jan 1,
2000
[[cc]yy]mmddHHMM[.ss] meaning 12:00:00 AM Jan 1,
2001
In this case, the date command will display a warning
and assume the mmddHHMM[[cc]yy][.ss] format,
setting the date to 01:00:00 AM Jan 1, 2000.
ENVIRONMENT VARIABLES [Toc] [Back] The following environment variables affect the execution
of date: Provides a default value for the internationalization
variables that are unset or null. If LANG is unset
or null, the corresponding value from the default locale
is used. If any of the internationalization variables contain
an invalid setting, the utility behaves as if none of
the variables had been defined. If set to a non-empty
string value, overrides the values of all the other internationalization
variables. Determines the locale for the
interpretation of sequences of bytes of text data as characters
(for example, single-byte as opposed to multibyte
characters in arguments). Determines the locale for the
format and contents of diagnostic messages written to
standard error. Determines the format of the date and
time strings written by date. Determines the location of
message catalogues for the processing of LC_MESSAGES.
Determines the time zone in which the time and date are
written, unless the -u option is specified. If the TZ
variable is not set and the -u option is not specified, a
system default time zone is used.
Functions: gettimeofday(2)
Routines: ctime(3), getclock(3), setclock(3)
Standards: standards(5)
Command and Shell User's Guide
date(1)
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