date Linux and Unix 命令手册

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date         Linux and Unix 命令手册
本命令手册以实用，简洁为原则，对于已经消化的内容，不附加详细的注解。
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参考资料
l        
《Unix 技术手册》
l        
Solaris 8 date 命令帮助

常用用法
＊Solaris 8 帮助中的实例，分行显示日期和时间
bash-2.03# date '+DATE: %m/%d/%y%nTIME:%H:%M:%S'
DATE: 11/23/07
TIME:09:31:50
       Linux
的命令帮助没有这种实例，可见参考Solaris的更好。

＊     设置日期和时间， 设置为2000年1月1日 16:59
bash-2.03# date 010116592000
Sat Jan  1 16:59:00 CST 2000

＊Solaris 8 帮助中的实例，设置时间
bash-2.03# date 1234.56
Sat Jan  1 12:34:56 CST 2000

＊获取年月日
bash-2.03# date +%y-%m-%d
07-11-23
命令参考
＊Solaris 8 date
命令参考

bash-2.03# man date
Reformatting page.  Please Wait... done

User Commands                                            
date(1)

NAME
   
date - write the date and time

SYNOPSIS
   
/usr/bin/date [ -u ]  [  +
format  ]

     /usr/bin/date
[  -a
[ - ]  sss.fff  ]

   
/usr/bin/date [ -u ]  [  [ mmdd ]
HHMM  |  mmddHHMM
[ cc ]
   
yy  ]  [ .SS ]

   
/usr/xpg4/bin/date [ -u ]  [  +
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 will be 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(5).

   
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  will  be
         
sped  up  or
slowed  down until it has drifted
by the
         
number of seconds specified. Only the
super-user  may
         
adjust the time.

   
-u    Display (or set)  the
date  in  Greenwich
Mean  Time
         
(GMT-universal  time), bypassing
the normal conversion
         
to (or from) local time.

SunOS 5.8           Last change: 20 Apr 1999                    1

User Commands                                            
date(1)

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].

   
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 minus one

   
yy    Last 2 digits of the year
number

         
The month, day, year, 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

SunOS 5.8           Last change: 20 Apr 1999                    2

User Commands                                            
date(1)

         
according to the default format. The date command uses
         
TZ to determine the correct time zone information; see
         
environ(5).

EXAMPLES
   
Example 1: Generating output

   
The 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 command

     example# date 1234.56

   
sets the current time to 12:34:56.

ENVIRONMENT VARIABLES
   
See environ(5) for descriptions of the following environment
   
variables  that  affect
the  execution  of
date: 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(5) for descriptions of the  following
attri-
   
butes:


/usr/bin/date

SunOS 5.8           Last change: 20 Apr 1999                    3

User Commands                                            
date(1)

   
____________________________________________________________
   
|       ATTRIBUTE TYPE        |      
ATTRIBUTE VALUE       |
   
|_____________________________|_____________________________|
    |
Availability                |
SUNWcsu                     |
   
|_____________________________|_____________________________|
    |
CSI                         |
enabled                     |
   
|_____________________________|_____________________________|


/usr/xpg4/bin/date
   
____________________________________________________________
   
|       ATTRIBUTE TYPE        |      
ATTRIBUTE VALUE       |
   
|_____________________________|_____________________________|
    |
Availability                |
SUNWxcu4                    |
   
|_____________________________|_____________________________|
    |
CSI                         |
enabled                     |
   
|_____________________________|_____________________________|

SEE ALSO
   
strftime(3C),
attributes(5), environ(5), XPG4(5)

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 exam-
   
ple, 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 may 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'.

SunOS 5.8           Last change: 20 Apr 1999                    4

bash-2.03#
               
               
               

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