date(1) date(1)
NAME
date - print date and time or set system clock
SYNOPSIS
date [-u] [+format] Format 1
date [-a [-]ssss.fff] [-u] [newdate] Format 2
DESCRIPTION
date writes the current date and time on standard output (Format 1).
The form in which date outputs dates and times depends on the value of
the environment variable LCTIME or, if that is undefined or null, on
the value of LANG. If both are undefined or null, or if the required
database is not available, or if one of the NLS variables has an
invalid value, date acts as if in a non-internationalized system,
printing dates and times in American format.
If you are the system administrator, you can also use date to set the
system clock (Format 2); but you should not do this unless you are in
single-user mode and all file systems have been unmounted. Changing
the system clock may otherwise produce inconsistencies in the file
systems.
Mode of operation
The system operates in coordinated universal time UTC (Universal Time
Coordinated; synonymous with Greenwich Mean Time/GMT). date takes care
of conversions to and from UTC to local time. If the environment vari-
able TZ is defined, it is used to determine the timezone and to con-
vert UTC to local time [see sh(1), "Standard shell variables"].
OPTIONS
Format 1: Print date and time
date [-u] [+format]
No argument specified:
date prints the current date and time in a format governed by the
current locale.
-u Displays the current date and time in Greenwich Mean Time (GMT).
If the -u option is set, the +format specification is ignored.
+format
The format argument defines the output format for date. If format
contains blanks or tabs or other shell metacharacters which you
do not want the shell to interpret, you should enclose format in
single quotes: +'format'.
Page 1 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
format is essentially similar in format to the first argument of
the printf function in C or awk [see awk(1), printf(1), and the
C-function printf(3S)].
The output of date can be formatted by means of field descriptors
in the format argument. Field descriptors take the form of a per-
centage sign followed by a letter and are replaced in the output
by their values. All characters that are not part of a field
descriptor are copied to the output unmodified. The output is
always terminated with a newline character.
The following overview lists all legal field descriptors. Although
the field descriptors %h and %b are essentially identical, both
descriptors have been retained for compatibility reasons.
___________________________________________________________________
| %n | newline character |
|_____|____________________________________________________________|
| %t | tab character |
|_____|____________________________________________________________|
| %c | date and time in the default format of the current locale |
|_____|____________________________________________________________|
| %C | century (first two digits of the year, 00-99) |
|_____|____________________________________________________________|
| %D | date in the format %m/%d/%y |
|_____|____________________________________________________________|
| %x | date in the format of the current locale |
|_____|____________________________________________________________|
| %y | year (last two digits of the year, 00-99) |
|_____|____________________________________________________________|
| %Y | year (all four digits of the year) |
|_____|____________________________________________________________|
| %m | month (01 to 12) |
|_____|____________________________________________________________|
| %h | month (in letters, abbreviated) in the format of the |
| | current locale |
|_____|____________________________________________________________|
| %b | identical to %h |
|_____|____________________________________________________________|
| %B | month (in letters, in full) in the format of of the |
| | current locale |
|_____|____________________________________________________________|
| %W | week number of the year (00 to 53, with Monday as the |
| | first day of the week). All days before the first Monday |
| | in January belong to week 0. |
|_____|____________________________________________________________|
| %V | week number of the year (01 to 53, with Monday as the |
| | first day of the week). The first week in January is |
| | counted as week 1 if it contains at least 4 days. Other- |
| | wise this week is counted as week 53 of the previous year |
| | (in accordance with ISO 8601). |
|_____|____________________________________________________________|
Page 2 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
___________________________________________________________________
| %U | week number of the year (00 to 53, with Sunday as the |
| | first day of the week). All days before the first Sunday |
| | in January belong to week 0. |
|_____|____________________________________________________________|
| %j | day of year (001 to 366) |
|_____|____________________________________________________________|
| %d | day of month (01 to 31) |
|_____|____________________________________________________________|
| %e | day of month (1 to 31, single-digit numbers preceded by a |
| | blank) |
|_____|____________________________________________________________|
| %a | abbreviated weekday name in the format of the current |
| | locale |
|_____|____________________________________________________________|
| %A | full weekday name in the format of the current locale |
|_____|____________________________________________________________|
| %w | day of week (0 to 6, Sunday = 0) |
|_____|____________________________________________________________|
| %u | day of week (1 to 7, Monday = 1) |
|_____|____________________________________________________________|
| %R | time in the format %H:%M |
|_____|____________________________________________________________|
| %T | time in the format %H:%M:%S |
|_____|____________________________________________________________|
| %X | time in the format of the current locale |
|_____|____________________________________________________________|
| %r | time in a.m./p.m. notation, as %I:%M:%S %p |
|_____|____________________________________________________________|
| %H | hour (00 to 23) |
|_____|____________________________________________________________|
| %I | hour (01 to 12) |
|_____|____________________________________________________________|
| %p | string containing ante-meridian or post-meridian indicator|
| | (a.m./p.m. affix) in the format of the current locale. |
|_____|____________________________________________________________|
| %M | minute (00 to 59) |
|_____|____________________________________________________________|
| %S | second (00 to 61) |
|_____|____________________________________________________________|
| %Z | timezone name, or no output if no timezone exists |
| | (governed by the value of the environment variable TZ, see|
| | sh(1), "Standard shell variables"). |
|_____|____________________________________________________________|
If an alternative representation is defined in your local envi-
ronment (e.g. before and after Christ) you can call it using
modified field descriptors. Modified field descriptors are in the
form %Eletter or %Oletter. The modified field descriptors that
can be used are listed in the overview below:
Page 3 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
If no alternative representation has been defined, all modified
field descriptors output the value of the current unmodified
field descriptors.
___________________________________________________________________
| %Ec | date and time in the alternative format |
|_____|____________________________________________________________|
| %EC | name of the time period (e.g. "year") in the alternative |
| | representation |
|_____|____________________________________________________________|
| %Ex | date in the alternative format |
|_____|____________________________________________________________|
| %EX | time in the alternative format |
|_____|____________________________________________________________|
| %Ey | year in which the time period in the alternative represen-|
| | tation begins |
|_____|____________________________________________________________|
| %EY | year in the alternative representation |
|_____|____________________________________________________________|
| %Od | day of month in alternative numeric representation |
|_____|____________________________________________________________|
| %Oe | day of month in alternative numeric representation |
|_____|____________________________________________________________|
| %OH | hour (24-hour clock) in alternative numeric representation|
|_____|____________________________________________________________|
| %OI | hour (12-hour clock) in alternative numeric representation|
|_____|____________________________________________________________|
| %Om | month in alternative numeric representation |
|_____|____________________________________________________________|
| %OM | minutes in alternative numeric representation |
|_____|____________________________________________________________|
| %OS | seconds in alternative numeric representation |
|_____|____________________________________________________________|
| %Ou | weekday in the alternative format (Monday = 1) |
|_____|____________________________________________________________|
| %OU | week of the year in alternative numeric representation |
| | (same as for %U) |
|_____|____________________________________________________________|
| %OV | week of the year in alternative numeric representation |
| | (same as for %V) |
|_____|____________________________________________________________|
| %Ow | weekday in the alternative format (Sunday = 0) |
|_____|____________________________________________________________|
| %OW | week of the year in alternative numeric representation |
| | (same as for %W) |
|_____|____________________________________________________________|
| %Oy | year in the alternative format |
|_____|____________________________________________________________|
Page 4 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
Format 2: Set system clock
date [-a [-]ssss.fff] [-u] [newdate]
This format is for the system administrator only.
This format can be used to adjust the system clock or reset the date.
-a [-]ssss.fff
Adjusts the system clock time by ssss.fff seconds, where fff rep-
resents 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 changed by the specified amount (ssss may not exceed
2146).
-u Sets the date and time in Greenwich Mean Time (see option -u
under Format 1).
newdate
date sets the date and time of the system clock to the specified
value. The following can be entered for [mmdd]HHMM or
mmddHHMM[cc]yy:
____________________________________________________________________
| mm | dd | HH | MM | cc | yy |
|__________|__________|__________|__________|__________|____________|
| month | day | hour | minute | century | year (last |
| (01 - 12)| (01 - 31)| (00 - 23)| (00 - 59)| minus 1 | 2 digits) |
|__________|__________|__________|__________|__________|____________|
mmdd not specified:
date assumes that the specified time HHMM refers to the current
date.
cc not specified:
date assumes that the specified date mmddHHMMyy refers to the
current century.
The system clock should only be set in single-user mode when all file
systems have been unmounted. Changing the system clock may otherwise
lead to inconsistencies in the file systems.
Page 5 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
ERROR MESSAGES
Format 2
date: no permission.
You have tried to set the system clock as a normal user. This privi-
lege is reserved for the system administrator.
date: bad conversion.
You have attempted to set the system clock but have called date with
an incorrect format.
ENVIRONMENT VARIABLES
TZ If defined, the environment variable TZ contains information on
timezones. date uses TZ to determine the timezone and to convert
from UTC (Universal Time Coordinated) to local time and vice
versa.
The value of TZ consists of
- the standard timezone
- the offset from UTC in hours
- if relevant, the summer timezone with information for conver-
sions from standard time to summer time (daylight saving time)
and back.
A detailed description of TZ is provided under sh(1) in the sec-
tion "Standard shell variables".
LOCALE
The LCMESSAGES environment variable governs the language in which
message texts are displayed.
The LCTIME environment variable governs the language and the format
in which the date and time and the values of date and time constants
are displayed.
LCCTYPE governs character classes and character conversion (shift-
ing).
If LCMESSAGES, LCTIME or LCCTYPE is undefined or is defined as the
null string, it defaults to the value of LANG. If LANG is likewise
undefined or null, the system acts as if it were not international-
ized.
If any of the locale variables has an invalid value, the system acts
as if none of the variables were set.
Page 6 Reliant UNIX 5.44 Printed 11/98
date(1) date(1)
The LCALL environment variable governs the entire locale. LCALL
takes precedence over all the other environment variables which affect
internationalization.
EXAMPLES
Example 1: Printing date and time (LANG=EnUS.ASCII) [Format 1]
If you call date without arguments at 7:43 hours MET on March 27,
1997, and the system clock is set to the correct time, the following
will be printed:
Thu Mar 27 07:43:10 MET 1997
The command:
$ date '+DATE: %m/%d/%y%nTIME: %H:%M:%S'
generates the following output:
DATE: 03/27/97
TIME: 07:59:51
Example 2: Setting the system clock [Format 2]
You are working under the system administrator login root and want to
set the date and time to 16:30 on March 17, 1991. To do this, you must
first switch to single-user mode and unmount all file systems. You
then enter:
# date 0317163091
If you are calling date in the year 1991, there is no need to specify
the year.
SEE ALSO
cal(1), sysadm(1M), ctime(3C), printf(3S), LCTIME(4), environ(5).
Page 7 Reliant UNIX 5.44 Printed 11/98