date - set/list/convert dates

date sets the current date and time (with appropriate privilege), lists the current date or file dates, or converts dates.

Most common date forms are recognized, including those for crontab(1), ls(1), touch(1), and the default output from date itself.

If the date operand consists of 4, 6, 8, 10 or 12 digits followed by an optional . and two digits then it is interpreted as: HHMM.SS, ddHHMM.SS, mmddHHMM.SS, mmddHHMMyy.SS or yymmddHHMM.SS, or mmddHHMMccyy.SS or ccyymmddHHMM.SS. Conflicting standards and practice allow a leading or trailing 2 or 4 digit year for the 10 and 12 digit forms; the X/Open trailing form is used to disambiguate (touch(1) uses the leading form.) Avoid the 10 digit form to avoid confusion. The digit fields are:

cc

Century - 1, 19-20.

yy

Year in century, 00-99.

mm

Month, 01-12.

dd

Day of month, 01-31.

HH

Hour, 00-23.

MM

Minute, 00-59.

SS

Seconds, 00-60.

If more than one date operand is specified then:

1.

Each operand sets the reference date for the next operand.

2.

The date is listed for each operand.

3.

The system date is not set.

-a, --access-time|atime

List file argument access times.

-c, --change-time|ctime

List file argument change times.

-d, --date=date

Use date as the current date and do not set the system clock.

-e, --epoch

Output the date in seconds since the epoch. Equivalent to --format=%s.

-E, --elapsed

Interpret pairs of arguments as start and stop dates, sum the differences between all pairs, and list the result as a fmtelapsed(3) elapsed time on the standard output. If there are an odd number of arguments then the last time argument is differenced with the current time.

-f, --format=format

Output the date according to the strftime(3) format. For backwards compatibility, a first argument of the form +format is equivalent to -f format. format is in printf(3) style, where %field names a fixed size field, zero padded if necessary, and \c and \nnn sequences are as in C. Invalid %field specifications and all other characters are copied without change. field may be preceded by %- to turn off padding or %_ to pad with space, otherwise numeric fields are padded with 0 and string fields are padded with space. field may also be preceded by E for alternate era representation or O for alternate digit representation (if supported by the current locale.) Finally, an integral width preceding field truncates the field to width characters. The fields are:

%

% character

a

abbreviated weekday name

A

full weekday name

b

abbreviated month name

B

full month name

c

ctime(3) style date without the trailing newline

C

2-digit century

d

day of month number

D

date as mm/dd/yy

e

blank padded day of month number

f

locale default override date format

F

%ISO 8601:2000 standard date format; equivalent to Y-%m-%d

g

ls(1) -l recent date with hh:mm

G

ls(1) -l distant date with yyyy

h

abbreviated month name

H

24-hour clock hour

i

international date(1) date with time zone type name

I

12-hour clock hour

j

1-offset Julian date

J

0-offset Julian date

k

date(1) style date

K

all numeric date; equivalent to %Y-%m-%d+%H:%M:%S; %_[EO]K for space separator, %OK adds .%N, %EK adds %.N%z, %_EK adds .%N %z

l

ls(1) -l date; equivalent to %Q/%g/%G/

L

locale default date format

m

month number

M

minutes

n

newline character

N

nanoseconds 000000000-999999999

p

meridian (e.g., AM or PM)

q

time zone type name (nation code)

Q

<del>recent<del>distant<del>: <del> is a unique delimter character; recent format for recent dates, distant format otherwise

r

12-hour time as hh:mm:ss meridian

R

24-hour time as hh:mm

s

number of seconds since the epoch; .prec preceding s appends prec nanosecond digits, 9 if prec is omitted

S

seconds 00-60

t

tab character

T

24-hour time as hh:mm:ss

u

weekday number 1(Monday)-7

U

week number with Sunday as the first day

V

ISO week number (i18n is fun)

w

weekday number 0(Sunday)-6

W

week number with Monday as the first day

x

locale date style that includes month, day and year

X

locale time style that includes hours and minutes

y

2-digit year (you'll be sorry)

Y

4-digit year

z

time zone SHHMM west of GMT offset where S is + or -, use pad _ for SHH:MM

Z

time zone name

=[=][-+]flag

set (default or +) or clear (-) flag for the remainder of format, or for the remainder of the process if == is specified. flag may be:

l

enable leap second adjustments

n

convert %S as %S.%N

u

UTC time zone

#

equivalent to %s

?alternate

use alternate format if a default format override has not been specified, e.g., ls(1) uses "%?%l"; export TM_OPTIONS="format='override'" to override the default

-i, --incremental|adjust

Set the system time in incrementatl adjustments to avoid complete time shift shock. Negative adjustments still maintain monotonic increasing time. Not available on all systems.

-L, --last

List only the last time for multiple date operands.

-l, --leap-seconds

Include leap seconds in time calculations. Leap seconds after the ast library release date are not accounted for.

-m, --modify-time|mtime

List file argument modify times.

-n, --network

Set network time. On by default; -n means --nonetwork.

-p, --parse=format

Add format to the list of strptime(3) parse conversion formats. format follows the same conventions as the --format option, with the addition of these format fields:

|

If the format failed before this point then restart the parse with the remaining format.

&

Call the tmdate(3) heuristic parser. This is is the default when --parse is omitted.

-R, --rfc-2822

List date and time in RFC 2822 format (%a, %-e %h %Y %H:%M:%S %z).

-T, --rfc-3339=type

List date and time in RFC 3339 format according to type:

date

(%Y-%m-%d)

seconds

(%Y-%m-%d %H:%M:%S%_z)

ns|nanoseconds

(%Y-%m-%d %H:%M:%S.%N%_z)

-s, --show

Show the date without setting the system time.

-u, --utc|gmt|zulu|universal

Output dates in coordinated universal time (UTC).

-U, --unelapsed=scale

Interpret each argument as fmtelapsed(3) elapsed time and list the strelapsed(3) 1/scale seconds.

-z, --list-zones

List the known time zone table and exit. The table columns are: country code, standard zone name, savings time zone name, minutes west of UTC, and savings time minutes offset. Blank or empty entries are listed as - .

crontab(1), ls(1), touch(1), fmtelapsed(3), strftime(3), strptime(3), tm(3)

version

date (AT&T Research) 2011-01-27

author

Glenn Fowler <gsf@research.att.com>

author

David Korn <dgk@research.att.com>

copyright

Copyright © 1992-2012 AT&T Intellectual Property

license

http://www.eclipse.org/org/documents/epl-v10.html