date (Unix)
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Unix date command
The Unix date command displays the time and date. The super-user can use it to set the system clock.
Contents
[hide]
1 Usage
2 Formatting
3 Options
4 Examples
5 Setting the date
6 See also
7 External links
[edit] Usage
With no options, the date command displays the current date and time, including the abbreviated day name, abbreviated month name, day of the month, the time separated by colons, the timezone name, and the year. For example:
$date
Fri Jul 27 14:12:06 EDT 2007
Note that the implementation of the date command differs between Unix flavors. Specifically the GNU coreutils based command is much different than other POSIX implementations.
[edit] Formatting
To format a date provide a string beginning with + .
Format specifiers (format string starts with +) Specifier Description Values/Example
Day
%a weekday, abbreviated Thu
%A weekday, full Thursday
%d day of the month (dd), zero padded 23
%e day of the month (dd) 23
%j day of year, zero padded 001-366
%u day of week starting with Monday (1), i.e. mtwtfss 4
%w day of week starting with Sunday (0), i.e. smtwtfs 4
Week
%U week number Sunday as first day of week 01–53
%W week number Monday as first day of week 01–53
%V week of the year 01–53
Month
%m mm month 06
%h Mon Jun
%b Mon, locale's abbreviated Jun
%B locale's full month, variable length June
Year
%y yy two digit year 00–99
%Y ccyy year 2011
%g 2-digit year corresponding to the %V week number
%G 4-digit year corresponding to the %V week number
Century
%C cc century 00–99
Date
%D mm/dd/yy 06/23/11
%x locale's date representation (mm/dd/yy) 06/23/2011
%F %Y-%m-%d 2011-06-23
Hours
%l (Lowercase L) hour (12 hour clock) 12
%I (Uppercase I) hour (12 hour clock) zero padded 12
%k hour (24 hour clock) 12
%H hour (24 hour clock) zero padded 12
%p locale's upper case AM or PM (blank in many locales) PM
%P locale's lower case am or pm pm
Minutes
%M MM minutes 21
Seconds
%s seconds since 00:00:00 1970-01-01 UTC (Unix epoch) 1308831708
%S SS second 00–60
(The 60 is necessary to accommodate a leap second)
%N nanoseconds 000000000–999999999
Time
%r hours, minutes, seconds (12-hour clock) 12:21:48 PM
%R hours, minutes (24 hour clock) hh:mm e.g. 12:21
%T hours, minutes, seconds (24-hour clock) 12:21:48
%X locale's time representation (%H:%M:%S)
Date and Time
%c locale's date and time Sat Nov 04 12:02:33 EST 1989
Time zone
%z -zzzz RFC-822 style numeric timezone -0500
%Z time zone (e.g., EDT) nothing if no time zone is determinable EST
literals: %n newline %% percent %t horizontal tab
By default, date pads numeric fields with zeroes.
GNU date, but not BSD date, recognizes - (hyphen) do not pad the field and _ (underscore) pad the field with spaces between % and a numeric directive.
TZ Specifies the timezone, unless overridden by command line parameters. If neither is specified, the setting from /etc/localtime is used.
[edit] Options
-d, -de=string display time described by string, not now.
-e=datefile like de once for each line of datefile
-s, --set=string set time described by string
-n don't synchronize the clocks on groups of machines using the utility timed(8). By default, if timed is running, date will set the time on all of the machines in the local group. -n inhibites that.
-u Display or set the date in UTC (universal) time.
date [-u|--utc|--universal] [mmddHHMM[[cc]yy][[.SS]] The only valid option for this form specifies Coordinated Universal Time.
-u GMT ex: Sat Feb 5 14:49:42 GMT 2005
--utc, --universal Coordinated Universal Time local TZ Sat Feb 5 09:49:59 EST 2005
-ITIMESPEC, --iso-8601[=TIMESPEC] output date/time in ISO 8601 format. TIMESPEC=date for date only, hours, minutes, or seconds for date and time to the indicated precision.
--iso-8601 without TIMESPEC defaults to `date'.
-R, --rfc-822 output RFC-822 compliant date string, example: Wed, 16 Dec 2009 15:18:11 +0100
--help
The Single Unix Specification (SUS) mandates only one option: -u, where the date and time is printed as if the timezone was UTC+0. Other Unix and Unix-like systems provide extra options.
[edit] Examples
date "+%m/%d/%y"
7/4/06
date "+%Y%m%d"
20060704
To assign the time to a variable
START=`date '+%r'`
echo $START
03:06:02 PM
sleep 5
echo $START
03:06:02 PM
N.B. the variable has the time when it was assigned.
Yesterday assigned to variable
DATE=$(date -d yesterday +"%Y%m%d")
echo $DATE
20060704
To show the time in a different timezone, the TZ environment variable is read, Timezone types is found in /usr/share/zoneinfo
OLDTZ=$TZ
export TZ=GMT; echo "GMT: `date +\"%F %R (%Z)\"`"
GMT: 2008-10-31 12:30 (GMT)
export TZ=Europe/Stockholm; echo "Stockholm: `date +\"%F %R (%Z)\"`"
Stockholm: 2008-10-31 13:30 (CET)
export TZ=Asia/Kuala_Lumpur; echo "Kuala Lumpur: `date +\"%F %R (%Z)\"`"
Kuala Lumpur: 2008-10-31 20:30 (MYT)
export TZ=US/Central; echo "Dallas: `date +\"%F %R (%Z)\"`"
Dallas: 2008-10-31 07:30 (CDT)
export TZ=$OLDTZ
Other valid time strings
date +"%Y%m%d" -d sunday # GNU date
20060709
date +"%Y%m%d" -d last-sunday # GNU date
20060702
date +"%Y%m%d" -d last-week # GNU date
date -v -1m +"%Y%m%d" # BSD date
20060627
date +"%Y%m%d" -d last-month # GNU date
date -v -1w +"%Y%m%d" # BSD date
20060604
date +"%Y%m%d" -d last-year # GNU date
date -v -1y +"%Y%m%d" # BSD date
20050704
date +"%Y%m%d" -d next-week # GNU date
date -v 1w +"%Y%m%d" # BSD date
20060711
date +"%Y%m%d" -d next-month # GNU date
date -v 1m +"%Y%m%d" # BSD date
20060804
date +"%Y%m%d" -d next-year # GNU date
date -v 1y +"%Y%m%d" # BSD date
20070704
To show the time in seconds since 1970-01-01 (Unix epoch):
date +"%s" -d "Fri Apr 24 13:14:39 CDT 2009"
1240596879
To convert Unix epoch time (seconds since 1970-01-01) to a human readable format:
date -d "UTC 1970-01-01 1240596879 secs"
Fri Apr 24 13:14:39 CDT 2009
Or:
date -ud @1000000000
Sun Sep 9 01:46:40 UTC 2001
[edit] Setting the date
The XSI extension to the SUS specifies that the date command can also be used to set the date. The new date is specified as an option to date in the format MMddhhmm[[cc]yy], where MM specifies the two-digit numeric month, dd specifies the two-digit numeric day, hh specifies the two-digit numeric hour, mm specifies the two-digit numeric minutes. Optionally cc specifies the first two digits of the year, and yy specifies the last two digits of the year.
Other Unix and Unix-like systems may set different options or date formats for date, for example, on some systems to set the current date and time to September 8, 2004 01:22 you type:
date --set="20040908 01:22"
[edit] See also
List of Unix programs
Unix time, i.e. number of seconds elapsed since midnight UTC of January 1, 1970 Epoch
time and date
Cron process for scheduling jobs to run on a given date.
[edit] External links
date: write the date and time – Commands & Utilities Reference, The Single UNIX® Specification, Issue 7 from The Open Group
date(1): print or set the system date and time – Linux User Commands Manual
date(1) – FreeBSD General Commands Manual
UNIX date command examples.
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http://en.wikipedia.org/wiki/Date_%28Unix%29
แสดงบทความที่มีป้ายกำกับ date แสดงบทความทั้งหมด
แสดงบทความที่มีป้ายกำกับ date แสดงบทความทั้งหมด
25540623
date
date
Display or change the date.
Syntax
date [option]... [+Format]
date [option] [MMDDhhmm[[CC]YY][.ss]]
`date' with no arguments prints the current time and date, in the format of the %c directive (described below).
If given an argument that starts with a +, date prints the current time and date (or the time and date specified by the --date option, see below) in the format defined by that argument, which is the same as in the strftime function.
Except for directives, which start with %, characters in the format string are printed unchanged. The directives are described below.
Options:
-d, --date=String Display time described by String, instead of `now'
this can be in almost any common format.
It can contain month names, timezones, `am' and `pm',
`yesterday', `ago', `next', etc.
-f, --file=DateFile like --date once for each line of DateFile
If DateFile is `-', use standard input. This is
useful when you have many dates to process,
because the system overhead of starting up the
`date' executable many times can be considerable.
-I, --iso-8601[=Timespec] Output an ISO-8601 compliant date/time string., `%Y-%m-%d'.
Timespec=`date' (or missing) for date only,
`hours', `minutes', or `seconds' for date and
time to the indicated precision.
If showing any time terms, then include the time zone
using the format `%z'. If `--utc' is also specified,
use `%Z' in place of `%z'.
-r, --reference=File Display the last modification time of File
-R, --rfc-822 Output RFC-822 compliant date string
-s, --set=String Set time described by String (see -d above)
-u, --utc, --universal Print or set Coordinated Universal Time
--help Display this help and exit
--version output version information and exit
Format controls the output as follows. The only valid option for the second form (MMDDhhmm[[CC]YY][.ss])will specify Coordinated Universal Time.
Interpreted sequences are:
Date:
D Date in mm/dd/yy format (06/14/06)
x Date in standard format for locale (09/12/07 for English-US)
Year:
C Century (20 for 2006)
Y Year in 4-digit format (2006)
y Year in 2-digit format (06)
G Same as 'Y'
g Same as 'y'
Month:
b Month name - abbreviated (Jan)
B Month name - full (January)
h Same as 'b'
m Month number (06)
Week:
W Week of the year (00-52)
V Week of the year (01-53)
U Same as 'W'
Day:
a Day of the week - abbreviated name (Mon)
A Day of the week - full name (Monday)
u Day of the week - number (Monday = 1)
d Day of the month - 2 digits (05)
e Day of the month - digit preceded by a space ( 5)
j Day of the year - (1-366)
w Same as 'u'
Time:
p AM or PM
r Time in 12-hour format (09:15:36 AM)
R Time in 24-hour format - no seconds (17:45)
T Time in 24 hour format (17:45:52)
X Same as 'T'
Z Time zone offset from UTC (-07)
Hour:
H Hour in 24-hour format (17)
I Hour in 12 hour format (05)
k Same as 'H'
l Same as 'I' (Upper-case I = Lower-case L)
Minutes & Seconds:
M Minutes (35)
S Seconds (05)
s Seconds elapsed since January 1, 1970 00:00:00 (1150451174.95705)
Here are the same format codes in alphabetical order:
%% a literal %
%a locale's abbreviated weekday name (Sun..Sat)
%A locale's full weekday name, variable length (Sunday..Saturday)
%b locale's abbreviated month name (Jan..Dec)
%B locale's full month name, variable length (January..December)
%c locale's date and time (Sat Nov 04 12:02:33 EST 1989)
%d day of month (01..31)
%D date (mm/dd/yy)
%e day of month, blank padded ( 1..31)
%h same as %b, locale's abbreviated month name (Jan..Dec)
%H hour :24 hour(00..23)
%I hour :12 hour(01..12)
%j day of year (001..366)
%k hour :24 hour(00..23)
%l hour :12 hour(01..12)
%m month (01..12)
%M minute (00..59)
%n a newline
%p locale's AM or PM
%r time, 12-hour (hh:mm:ss [AP]M)
%s seconds since 00:00:00, Jan 1, 1970 (a GNU extension)
Note that this value is defined by the localtime system
call. It isn't changed by the `--date' option.
%S second (00..60)
%t a horizontal tab
%T time, 24-hour (hh:mm:ss)
%U week number of year with Sunday as first day of week (00..53)
%V week number of year with Monday as first day of week (01..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. (See the ISO 8601: 1988 standard.)
%w day of week (0..6); 0 represents Sunday
%W week number of year with Monday as first day of week (00..53)
%x locale's date representation (mm/dd/yy)
%X locale's time representation (%H:%M:%S)
%y last two digits of year (00..99)
%Y year (1970...)
%z RFC-822 style numeric timezone (-0500) (a nonstandard extension)
This value reflects the _current_ time zone.
It isn't changed by the `--date' option.
%Z time zone (e.g., EDT), or nothing if no time zone is determinable
This value reflects the _current_ time zone.
It isn't changed by the `--date' option.
By default, date pads numeric fields with zeroes. GNU date recognizes the following modifiers between % and a numeric directive.
- (hyphen) do not pad the field; useful if the output is intended for human consumption.
_ (underscore) pad the field with spaces; useful if you need a fixed number of characters in the output, but zeroes are too distracting.
The - and _ are GNU extensions. Here is an example illustrating the differences:
date +%d/%m -d "Feb 1"
=> 01/02
date +%-d/%-m -d "Feb 1"
=> 1/2
date +%_d/%_m -d "Feb 1"
=> 1/ 2
Setting the time
If given an argument that does not start with +, date sets the system clock to the time and date specified by that argument (as described below). You must have appropriate privileges to set the system clock. The --date and --set options may not be used with such an argument. The --universal option may be used with such an argument to indicate that the specified time and date are relative to Coordinated Universal Time rather than to the local time zone.
The argument must consist entirely of digits, which have the following meaning:
MM month
DD day within month
HH hour
MM minute
CC first two digits of year (optional)
YY last two digits of year (optional)
SS second (optional)
The `--set' option also sets the system clock; see the examples below.
Examples
Print the date of the day before yesterday:
$ date --date='2 days ago'
Rename a file with the current date and time
$ STAMPME=$HOME/demo_file_$(date +%Y%m%d-%H%M).txt
$ mv $HOME/demo_file $STAMPME
Print the date of the day three months and one day hence:
$ date --date='3 months 1 day'
Print the day of year of Christmas in the current year:
$ date --date='25 Dec' +%j
Print the current full month name and the day of the month:
$ date '+%B %d'
But this may not be what you want because for the first nine days of the month, the `%d' expands to a zero-padded two-digit field, for example date -d 1may '+%B %d' will print `May 01'.
* Print a date without the leading zero for one-digit days of the month, you can use the (GNU extension) `-' modifier to suppress the padding altogether.
$ date -d=1may '+%B %-d'
Print the current date and time in the format required by many non-GNU versions of `date' when setting the system clock:
$ date +%m%d%H%M%Y.%S
Set the system date and time
$ date --set="2002-6-29 11:59 AM"
Set the system clock forward by two minutes:
$ date --set='+2 minutes'
Print the date in the format specified by RFC-822, use date --rfc
I just did and saw this:
Mon, 25 Mar 1996 23:34:17 -0600
To convert a date string to the number of seconds since the epoch (which is 1970-01-01 00:00:00 UTC), use the `--date' option with the `%s' format. That can be useful in sorting and/or graphing and/or comparing data by date. The following command outputs the number of the seconds since the epoch for the time one second later than the epoch, but in time zone five hours later (Cambridge, Massachusetts), thus a total of five hours and one second after the epoch:
$ date --date='1970-01-01 00:00:01 UTC +5 hours' +%s
18001
Suppose you had _not_ specified time zone information in the example above. Then, date would have used your computer's idea of
the time zone when interpreting the string. Here's what you would get if you were in Greenwich, England:
# local time zone used
$ date --date='1970-01-01 00:00:01' +%s
1
If you're sorting or graphing dated data, your raw date values may be represented as seconds since the epoch. But few people can
look at the date `946684800' and casually note "Oh, that's the first second of the year 2000."
$ date --date='2000-01-01 UTC' +%s
946684800
To convert such an unwieldy number of seconds back to a more readable form, use a command like this:
$ date -d '1970-01-01 946684800 sec' +"%Y-%m-%d %T %z"
2000-01-01 00:00:00 +0000
"Carpe Diem - Seize the day" - Horace
Related:
cal - Display a calendar
crontab - Schedule a command to run at a later time
time - Measure Program Resource Use
times - User and system times
touch - Change file timestamps
Equivalent Windows command: DATE - Display or set the dat
******************
http://ss64.com/bash/date.html
Display or change the date.
Syntax
date [option]... [+Format]
date [option] [MMDDhhmm[[CC]YY][.ss]]
`date' with no arguments prints the current time and date, in the format of the %c directive (described below).
If given an argument that starts with a +, date prints the current time and date (or the time and date specified by the --date option, see below) in the format defined by that argument, which is the same as in the strftime function.
Except for directives, which start with %, characters in the format string are printed unchanged. The directives are described below.
Options:
-d, --date=String Display time described by String, instead of `now'
this can be in almost any common format.
It can contain month names, timezones, `am' and `pm',
`yesterday', `ago', `next', etc.
-f, --file=DateFile like --date once for each line of DateFile
If DateFile is `-', use standard input. This is
useful when you have many dates to process,
because the system overhead of starting up the
`date' executable many times can be considerable.
-I, --iso-8601[=Timespec] Output an ISO-8601 compliant date/time string., `%Y-%m-%d'.
Timespec=`date' (or missing) for date only,
`hours', `minutes', or `seconds' for date and
time to the indicated precision.
If showing any time terms, then include the time zone
using the format `%z'. If `--utc' is also specified,
use `%Z' in place of `%z'.
-r, --reference=File Display the last modification time of File
-R, --rfc-822 Output RFC-822 compliant date string
-s, --set=String Set time described by String (see -d above)
-u, --utc, --universal Print or set Coordinated Universal Time
--help Display this help and exit
--version output version information and exit
Format controls the output as follows. The only valid option for the second form (MMDDhhmm[[CC]YY][.ss])will specify Coordinated Universal Time.
Interpreted sequences are:
Date:
D Date in mm/dd/yy format (06/14/06)
x Date in standard format for locale (09/12/07 for English-US)
Year:
C Century (20 for 2006)
Y Year in 4-digit format (2006)
y Year in 2-digit format (06)
G Same as 'Y'
g Same as 'y'
Month:
b Month name - abbreviated (Jan)
B Month name - full (January)
h Same as 'b'
m Month number (06)
Week:
W Week of the year (00-52)
V Week of the year (01-53)
U Same as 'W'
Day:
a Day of the week - abbreviated name (Mon)
A Day of the week - full name (Monday)
u Day of the week - number (Monday = 1)
d Day of the month - 2 digits (05)
e Day of the month - digit preceded by a space ( 5)
j Day of the year - (1-366)
w Same as 'u'
Time:
p AM or PM
r Time in 12-hour format (09:15:36 AM)
R Time in 24-hour format - no seconds (17:45)
T Time in 24 hour format (17:45:52)
X Same as 'T'
Z Time zone offset from UTC (-07)
Hour:
H Hour in 24-hour format (17)
I Hour in 12 hour format (05)
k Same as 'H'
l Same as 'I' (Upper-case I = Lower-case L)
Minutes & Seconds:
M Minutes (35)
S Seconds (05)
s Seconds elapsed since January 1, 1970 00:00:00 (1150451174.95705)
Here are the same format codes in alphabetical order:
%% a literal %
%a locale's abbreviated weekday name (Sun..Sat)
%A locale's full weekday name, variable length (Sunday..Saturday)
%b locale's abbreviated month name (Jan..Dec)
%B locale's full month name, variable length (January..December)
%c locale's date and time (Sat Nov 04 12:02:33 EST 1989)
%d day of month (01..31)
%D date (mm/dd/yy)
%e day of month, blank padded ( 1..31)
%h same as %b, locale's abbreviated month name (Jan..Dec)
%H hour :24 hour(00..23)
%I hour :12 hour(01..12)
%j day of year (001..366)
%k hour :24 hour(00..23)
%l hour :12 hour(01..12)
%m month (01..12)
%M minute (00..59)
%n a newline
%p locale's AM or PM
%r time, 12-hour (hh:mm:ss [AP]M)
%s seconds since 00:00:00, Jan 1, 1970 (a GNU extension)
Note that this value is defined by the localtime system
call. It isn't changed by the `--date' option.
%S second (00..60)
%t a horizontal tab
%T time, 24-hour (hh:mm:ss)
%U week number of year with Sunday as first day of week (00..53)
%V week number of year with Monday as first day of week (01..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. (See the ISO 8601: 1988 standard.)
%w day of week (0..6); 0 represents Sunday
%W week number of year with Monday as first day of week (00..53)
%x locale's date representation (mm/dd/yy)
%X locale's time representation (%H:%M:%S)
%y last two digits of year (00..99)
%Y year (1970...)
%z RFC-822 style numeric timezone (-0500) (a nonstandard extension)
This value reflects the _current_ time zone.
It isn't changed by the `--date' option.
%Z time zone (e.g., EDT), or nothing if no time zone is determinable
This value reflects the _current_ time zone.
It isn't changed by the `--date' option.
By default, date pads numeric fields with zeroes. GNU date recognizes the following modifiers between % and a numeric directive.
- (hyphen) do not pad the field; useful if the output is intended for human consumption.
_ (underscore) pad the field with spaces; useful if you need a fixed number of characters in the output, but zeroes are too distracting.
The - and _ are GNU extensions. Here is an example illustrating the differences:
date +%d/%m -d "Feb 1"
=> 01/02
date +%-d/%-m -d "Feb 1"
=> 1/2
date +%_d/%_m -d "Feb 1"
=> 1/ 2
Setting the time
If given an argument that does not start with +, date sets the system clock to the time and date specified by that argument (as described below). You must have appropriate privileges to set the system clock. The --date and --set options may not be used with such an argument. The --universal option may be used with such an argument to indicate that the specified time and date are relative to Coordinated Universal Time rather than to the local time zone.
The argument must consist entirely of digits, which have the following meaning:
MM month
DD day within month
HH hour
MM minute
CC first two digits of year (optional)
YY last two digits of year (optional)
SS second (optional)
The `--set' option also sets the system clock; see the examples below.
Examples
Print the date of the day before yesterday:
$ date --date='2 days ago'
Rename a file with the current date and time
$ STAMPME=$HOME/demo_file_$(date +%Y%m%d-%H%M).txt
$ mv $HOME/demo_file $STAMPME
Print the date of the day three months and one day hence:
$ date --date='3 months 1 day'
Print the day of year of Christmas in the current year:
$ date --date='25 Dec' +%j
Print the current full month name and the day of the month:
$ date '+%B %d'
But this may not be what you want because for the first nine days of the month, the `%d' expands to a zero-padded two-digit field, for example date -d 1may '+%B %d' will print `May 01'.
* Print a date without the leading zero for one-digit days of the month, you can use the (GNU extension) `-' modifier to suppress the padding altogether.
$ date -d=1may '+%B %-d'
Print the current date and time in the format required by many non-GNU versions of `date' when setting the system clock:
$ date +%m%d%H%M%Y.%S
Set the system date and time
$ date --set="2002-6-29 11:59 AM"
Set the system clock forward by two minutes:
$ date --set='+2 minutes'
Print the date in the format specified by RFC-822, use date --rfc
I just did and saw this:
Mon, 25 Mar 1996 23:34:17 -0600
To convert a date string to the number of seconds since the epoch (which is 1970-01-01 00:00:00 UTC), use the `--date' option with the `%s' format. That can be useful in sorting and/or graphing and/or comparing data by date. The following command outputs the number of the seconds since the epoch for the time one second later than the epoch, but in time zone five hours later (Cambridge, Massachusetts), thus a total of five hours and one second after the epoch:
$ date --date='1970-01-01 00:00:01 UTC +5 hours' +%s
18001
Suppose you had _not_ specified time zone information in the example above. Then, date would have used your computer's idea of
the time zone when interpreting the string. Here's what you would get if you were in Greenwich, England:
# local time zone used
$ date --date='1970-01-01 00:00:01' +%s
1
If you're sorting or graphing dated data, your raw date values may be represented as seconds since the epoch. But few people can
look at the date `946684800' and casually note "Oh, that's the first second of the year 2000."
$ date --date='2000-01-01 UTC' +%s
946684800
To convert such an unwieldy number of seconds back to a more readable form, use a command like this:
$ date -d '1970-01-01 946684800 sec' +"%Y-%m-%d %T %z"
2000-01-01 00:00:00 +0000
"Carpe Diem - Seize the day" - Horace
Related:
cal - Display a calendar
crontab - Schedule a command to run at a later time
time - Measure Program Resource Use
times - User and system times
touch - Change file timestamps
Equivalent Windows command: DATE - Display or set the dat
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http://ss64.com/bash/date.html
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