extracting date information


Add a date suffix to your files before editing!

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TESTING the addition of a suffix to a file on HP-UX 10.20

touch file.`date +%o%b%d` -rw-r--r-- 1 jmeister tty 0 Nov 23 13:04 file.99Nov23

making a copy of a system file BEFORE editing

cp /etc/hosts /etc/hosts.`date +%o%b%d` (note: in Linux, use %y instead of %o for the year) -----------------------------------------------------

an EXAMPLE in a script

/usr/bin/echo "=====" | /usr/bin/tee -a `/usr/bin/hostname`.`/usr/bin/date +%o%b%d`.status (this creates a file with the hostname.99Nov23.status) example of a status checking script"

a variation of the suffix, all numeric

example using suffix to create a log file" extract: /usr/bin/cp /etc/hosts /sbin/root/setup/hosts.`date +'%y%m%d-%H'` /usr/bin/cp /etc/hosts /etc/hosts.`date +'%y%m%d-%H'` #########################################################

man page for DATE - HP-UX 10.20 - YMMV for other flavors. :)

Linux man page on date
 note: to capture man pages without formatting and save them as
a text file, type:    man date | col -b > /tmp/date   

 date(1)							     date(1)
 NAME
      date - display or set the date and time
 SYNOPSIS
      date [-u]
      date [-u] +format
      date [-u] mmddhhmm[yy]
 DESCRIPTION
      The date command displays or sets the current HP-UX system clock date
      and time.	 Since the HP-UX system operates in Coordinated Universal
      Time (UTC), date automatically converts to and from local standard or
      daylight/summer time, based on your TZ environment variable.  See
      "Environment Variables" in EXTERNAL INFLUENCES below.
    Options
      date recognizes the following option:
	   -u	Input and output values in Coordinated Universal Time (UTC),
		functionally equivalent to Greenwich Mean Time (GMT),
		instead of in local time.
    Formats
      The date command has two forms for displaying the date and time and
      one form for setting them.
	   date [-u]
		   Display the current date and time.  The output is the
		   same as for the %c formatting directive for all languages
		   except the C default language.  See "Formatting
		   Directives" and EXAMPLES below.
	   date [-u] +format
		   Display the current date and time according to formatting
		   directives specified in format, which is a string of zero
		   or more formatting directives and ordinary characters.
		   If it contains blanks, enclose it in apostrophes or
		   quotation marks.
		   A formatting directive has the following syntax:
			%[[-|0]width][.prec]char
		   where width specifies the field width, prec specifies the
		   precision, and char is the directive code.  See
		   "Formatting Directives" and "Field Width and Precision"
		   below for more details.
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 date(1)							     date(1)
		   All ordinary characters are copied unchanged into the
		   output string.
		   The output string is always terminated with a newline
		   character.
		   If + is specified and format is omitted, only a newline
		   is output.
	   date [-u] mmddhhmm[yy]
		   Set the HP-UX system clock to the date and time
		   specified.  You require the superuser privilege.
		   If you include the -u option, the specified date and time
		   is assumed to be in Coordinated Universal Time (UTC).
		   The numeric argument is interpreted left to right in
		   two-digit pairs as follows:
			mm   Month number [01-12].
			dd   Day number in the month [01-31].
			hh   Hour number (24-hour system) [00-23].
			mm   Minute number [00-59].
			yy   Last two digits of the year number [70-99, 00-
			     69 (1970-1999, 2000-2069)].  If omitted, the
			     current year is used.
		   If you attempt to set the date backwards, date generates
		   the warning,
			do you really want to run time backwards?[yes/no]
		   Type yes or the equivalent for your locale to set the
		   clock backwards; anything else to cancel the command.
		   When date is used to set the date, a pair of date change
		   records is written to the file /var/adm/wtmp.
		   (XPG4 only.) No warning is generated if date is set
		   backwards.
    Formatting Directives
      The following formatting directives, shown without the optional field
      width and precision specification, are replaced by the indicated
      characters.  If a directive is not one of the following, the result is
      undefined.
      The output for digits, characters, and words depends on the
      language/locale settings.	 See "Environment Variables" in EXTERNAL
      INFLUENCES below.
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 date(1)							     date(1)
      The examples assume that the date command was executed on Wednesday,
      January 12, 1994 at 7:45:58 p.m. Pacific Standard Time, using the C
      default language.
	   %a	Abbreviated weekday name.  For example, Wed.
	   %A	Full weekday name.  For example, Wednesday.
	   %b	Abbreviated month name.	 For example, Jan.
	   %B	Full month name.  For example, January.
	   %c	Current date and time representation.  For example, Wed Jan
		12 19:45:58 1994.
	   %C	Century (the year divided by 100 and truncated to an
		integer) as a two-digit decimal number [00-99].	 For
		example, 19.
	   %d	Day of the month as a two-digit decimal number [01-31].	 For
		example, 12.
	   %e	Day of the month as a two-character decimal number with
		leading space fill [" 1"-"31"].	 For example, 12.
	   %E	Combined Emperor/Era name and year.
	   %H	Hour (24-hour clock) as a two-digit decimal number [00-23].
		For example, 19.
	   %I	Hour (12-hour clock) as a two-digit decimal number [01-12].
		For example, 07.
	   %j	Day of the year as a three-digit decimal number [001-366].
		For example, 012.
	   %m	Month as a decimal two-digit number [01-12].  For example,
		01.
	   %M	Minute as a decimal two-digit number [00-59].  For example,
		45.
	   %n	Newline character.
	   %N	Emperor/Era name.
	   %o	Emperor/Era year.
	   %p	Equivalent of either AM or PM.	For example, PM.
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	   %S	Second as a two-digit decimal number (allows for possible
		leap seconds) [00-61].	For example, 58.
	   %t	Tab character.
	   %u	Weekday as a one-digit decimal number [1-7 (Monday-Sunday)].
		For example, 3.
	   %U	Week number of the year (Sunday as the first day of the
		week) as a two-digit decimal number [00-53].  All days that
		precede the first Sunday in the year are considered to be in
		week 00.  For example, 02.
	   %V	Week number of the year (Monday as the first day of the
		week) as a two-digit decimal number [01-53].  If the week
		containing January 1 has four or more days in the new year
		(January 1 is Thursday or sooner), it is designated as week
		01; otherwise, (January 1 is Friday or later), it is
		designated as week 53 of the previous year, and the next
		week is week 01.  For example, 02.
	   %w	Weekday as a one-digit decimal number [0-6 (Sunday-
		Saturday)].  For example, 3.
	   %W	Week number of the year (Monday as the first day of the
		week) as a two-digit decimal number [00-53].  All days that
		precede the first Monday in the year are considered to be in
		week 00.  For example, 02.
	   %x	Current date representation.  For example, 01/12/94.
	   %X	Current time representation.  For example, 19:45:58.
	   %y	Year without century as a two-digit decimal number [00-99].
		For example, 93.
	   %Y	Year with century as a four-digit decimal number [1970-
		2069].	For example, 1994.
	   %Z	Time zone name (or no characters if time zone cannot be
		determined).  For example, PST.
	   %%	The % character.
    Obsolescent Directives
      The following directives are provided for backward compatibility.	 It
      is recommended that the preceding directives be used instead.
	   %D	Date in usual U.S. format.  For example, 01/12/94.  Use %x
		or %m/%d/%y instead.
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	   %F	Full month name.  For example, January.	 Use %B instead.
	   %h	Abbreviated month name.	 For example, Jan.  Use %b instead.
	   %r	Time in 12-hour U.S. format.  For example, 07:45:58 PM.	 Use
		"%I:%M:%S %p" instead.
	   %T	Time in 24-hour U.S. format.  For example, 19:45:58.  Use %X
		or %H:%M:%S instead.
	   %z	Time zone name (or no characters if time zone cannot be
		determined).  For example, PST.	 Use %Z instead.
    Modified Formatting Directives
      Some Formatting Directives can be modified by the E and O modifier
      characters to indicate a different format or specification for the
      language specified in the LC_TIME environment variable.
      If the corresponding keyword (era, era_year, era_d_fmt, and alt_digit)
      is not specified or not supported, the unmodified field descriptor
      value is used.  The command
	   LC_ALL=language locale -ck era era_year era_d_fmt alt_digit
      displays the keywords and their values in the specified language (see
      locale(1)).
	   %EC	     The name of the base year in alternate representation.
	   %Ex	     Alternate date representation.
	   %Ey	     Offset from %EC (year only) in the alternate
		     representation.
	   %Od	     Day of month using the alternate numeric symbols.
	   %Oe	     Day of month using the alternate numeric symbols with
		     leading space-character fill if applicable.
	   %OH	     Hour (24-hour clock) using the alternate numeric
		     symbols.
	   %OI	     Hour (12-hour clock) using the alternate numeric
		     symbols.
	   %Om	     Month using the alternate numeric symbols.
	   %OM	     Minutes using the alternate numeric symbols.
	   %OS	     Seconds using the alternate numeric symbols.
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	   %OU	     Week number of the year (Sunday is the first day of the
		     week) using the alternate numeric symbols.
	   %Ow	     Weekday as number using the alternate numeric symbols
		     (Sunday=0).
	   %OW	     Weekday number of the year (Monday is the first day of
		     the week) using the alternate numeric symbols.
	   %Oy	     Year (offset from %C) in alternate representation.
    Field Width and Precision
      An optional field width and precision specification can immediately
      follow the initial % of a formatting directive in the following order:
	   [-|0]width  The decimal digit string width specifies a minimum
		       field width in which the result of the conversion is
		       right- or left-justified.  The default is right-
		       justified with space padding on the left.  If the
		       string starts with "-", the result is left-justified
		       with space padding on the right.	 If the string
		       starts with "0", the result is right-justified and
		       padded with zeros on the left.
	   .prec       The decimal digit string prec specifies the minimum
		       number of digits to appear for the d, H, I, j, m, M,
		       o, S, U, w, W, y, and Y numeric directives.  If a
		       directive supplies fewer digits than specified by the
		       precision, it will be expanded with leading zeros.
		       prec specifies the maximum number of characters to be
		       used from the a, A, b, B, c, D, E, F, h, n, N, p, r,
		       t, T, x, X, z, Z, and % text directives.	 If a
		       directive supplies more characters than specified by
		       the precision, excess characters are truncated on the
		       right.
      If no field width or precision is specified for a d, H, I, m, M, S, U,
      W, or y directive, the default is .2; for the j directive, the default
      is .3; for Y, the default is .4; for w, the default is .1.
 EXTERNAL INFLUENCES
    Environment Variables
      LC_CTYPE determines the interpretation of the bytes within the format
      string as single- and/or multi-byte characters.
      LC_NUMERIC determines the characters used to form numbers for those
      directives that produce numbers in the output.  The characters used
      are those defined by alt_digit (see locale(1) and ALT_DIGIT in
      langinfo(5)).
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 date(1)							     date(1)
      LC_TIME determines the content (for example, the weekday names
      produced by the %a directive) and format (for example, the current
      time representation produced by the %X directive) of date and time
      strings output by the date command.
      LC_MESSAGES determines the language in which messages (other than the
      date and time strings) are displayed.
      If LC_CTYPE, LC_NUMERIC, LC_TIME, or LC_MESSAGES is not specified or
      is null, it defaults to the value of LANG.
      If LANG is not specified or is null, it defaults to C (see lang(5)).
      If any internationalization variable contains an invalid setting, all
      internationalization variables default to C (see environ(5)).
      TZ determines the conversion between the system time in UTC and the
      time in the user's local time zone.  See environ(5) and tztab(4).	 TZ
      also determines the content (that is, the time-zone name produced by
      the %z and %Z directives) of date and time strings output by the date
      command.
      If TZ is not set or is set to the empty string, its default value is
      EST5EDT.
    International Code Set Support
      Single- and multi-byte character code sets are supported.
 DIAGNOSTICS
      The following messages may be displayed.
      bad conversion
	      The date/time specification is syntactically incorrect.  Check
	      that there are eight or ten decimal digits, with each pair in
	      the correct range.
      bad format character - c
	      The character c is not a valid format directive, field width
	      specifier, or precision specifier.
      do you really want to run time backwards?[yes/no]
	      The date/time you specified is earlier than the current clock
	      value.  Type yes (or the equivalent for your locale) to set
	      the clock backwards; anything else to cancel the command.
      no permission
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 date(1)							     date(1)
	      You need the superuser privilege to change the date.
 EXAMPLES
    Date in Different Languages
      Display the date.	 In this example, the TZ environment variable
      contains PST8PDT, and the language environment variables are set as
      noted.
      date    -> Fri Aug 20 15:03:37 PDT 1993  <- C (default)
      date -u -> Fri Aug 20 22:03:37 UTC 1993  <- C (default)
      date    -> Fri, Aug 20, 1993 03:03:37 PM <- en_US.roman8 (U.S. English)
      date    -> Fri. 20 Aug, 1993 03:03:37 PM <- en_GB.roman8 (U.K. English)
      date    -> 20/08/1993 15.47.47	       <- pt_PT.roman8 (Portuguese)
    Set Date
      Set the date to Oct 8, 12:45 a.m.
	   date 10080045
    Display Formatted Date
      Display the current date and time using a format.	 Note the use of
      quotation marks due to the blanks in the format.
	   date "+DATE: %m/%d/%y%nTIME: %H:%M:%S"
      The output resembles the following:
	   DATE: 10/08/87
	   TIME: 12:45:05
    Display Formatted Date Using Local Language Conversion
      With the date as set in the "Set Date" example above and LC_TIME set
      to de_De.roman8 (German):
	   date +'%-4.4h %2.1d %H:%M'
      generates output similar to:
	   Okt	 8 12:45
      where the month field is four characters long, flush-left, and space-
      padded on the right if the month name is shorter than four characters.
      The day field is two characters long, with leading zeros suppressed.
 WARNINGS
      The former HP-UX format directive A has been changed to W for ANSI
      compatibility.
      Changing the date while the system is running in multiuser mode should
      be avoided to prevent disrupting user-scheduled and time sensitive
      programs and processes.  Also, changing the date can cause make(1) and
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 date(1)							     date(1)
      the SCCS and cron(1M) subsystems to behave in an unexpected manner.
      The cron daemon should be killed prior to setting the date backwards,
      then restarted.  SCCS files should be checked with the val command
      (see val(1)) if deltas have been made while the clock was wrongly set.
      Currently, the maximum date supported is December 31, 2030 23:59:00
      UTC.
 AUTHOR
      date was developed by AT&T and HP.
 FILES
      /var/adm/wtmp
 SEE ALSO
      locale(1), nlsinfo(1), stime(2), ctime(3C), strftime(3C), tztab(4),
      environ(5), lang(5), langinfo(5).
 STANDARDS CONFORMANCE
      date: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2
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