This utility adds or subtracts days, hours, and/or minutes from a given date, and outputs the results in the specified format.

The default, if no adjustment is specified, is "-1d" (subtract one day).

Yest supports most date(1) format codes as well as a few of its own.

--help

Display help information.

--license

Display license information.

--version

Display version information. --input-date-format=str --idf=str

Specify the default format for date input. The str identifier may be:

	"ISO"	(Format: yyyy-mm-ddThh:mi)
	"JP"	(Format: yyyy/mm/dd-hh:mi)
	"EU"	(Format: dd/mm/yyyy-hh:mi)
	"US"	(Format: mm/dd/yyyy-hh:mi)

If the format can be determined by the data, it will be. The default format will only be used for ambiguous dates, such as "02/03/04".

adjustment

The adjustment can be any of the following:

[-|+]day-time

Day, hour and minute adjustment specification in the format "[-|+]day-hour:minute". For example: "+4-12:00".

[-|+]intd

Explicit day adjustment amount.

[-|+]inth

Explicit hour adjustment amount.

[-|+]intm

Explicit minute adjustment amount. You can specify a combination of day, hour and minute adjustments. For example: "yest +3d -2h" If no adjustment is specified, the default is "-1d".

date

Date to be altered. Default is today, current hour, minute and second. date should be specified in ISO date format: "yyyy-mm-dd" Hours and minutes may be included: "yyyy-mm-ddThh" (date + hour) "yyyy-mm-ddThh:mi" (date + hour and minute) (Note that the "T" before the time is a literal 'T') Other date formats recognized are: epoch seconds (seconds since 1/1/1970) "dd/mm/yyyy" or "mm/dd/yyyy" (if LANG="en_US*") Hours and minutes may be included as follows: "dd/mm/yyyy-hh" (date + hour) "dd/mm/yyyy-hh:mi" (date + hour and minute) If you specify a date but no time, the time output fields will, of course, be zero. Currently, {date} must be between January 1, 1970 and January 18, 2038.

format-string

String containing date output codes and, optionally, other text. Any text in the format-string that is not a recognized output code is passed through unchanged. This includes the "%" character if it is not followed by a recognized format character. For compatability with date(1), a leading "+" character in the format-string will be ignored.

If there are spaces or special characters in the string, it must be quoted. The program will recognize most echo-like escape conventions such as "\n" (newline) and "\t" (tab) in format-string, and octal escapes (\0nn) are supported. If only a day adjustment is specified, the default format-string is "%x". If adjustment includes a time element, the default format-string becomes "%x-%R".

%a

Abbreviated day of week ("Tue")

%A

Full day of week ("Tuesday")

%b

Month name abbreviated to 3 chars ("Oct")

%B

Full month name ("October")

%c

Equivalent to "%a %b %e %R %Z %Y"

%C

Century ("19")

%d

Day of month ("13")

%D

Equivalent to "%d/%m/%y" ("%m/%d/%y" US)

%e

Equivalent to "% d" (pad with space)

%f

Equivalent to "%A, %B %-dth, %Y - %I:%M:%S %P"

%F

Equivalent to "%Y-%m-%d"

%h

Equivalent to "%b"

%H

Hour (24 hour)

%I

Hour (12 hour)

%j

Day of year ("123")

%k

Equivalent to "% H" (pad with space)

%l

Equivalent to "% I" (pad with space)

%L

Last day of month

%m

Month number ("10")

%M

Minute

%n

Equivalent to "\n" (newline).

%p

"AM" or "PM" for the hour

%P

"am" or "pm" for the hour

%q

"1" if daylight savings time is active, "0" if not.

%r

Equivalent to "%I:%M:%S %p"

%R

Equivalent to "%H:%M"

%s

Number of seconds since 01/01/1970-00:00.

%S

Seconds.

%t

Equivalent to "\t" (tab).

%T

Equivalent to "%H:%M:%S"

%u

Numeric day of week: 1-7 (1=Monday).

%w

Numeric day of week: 0-6 (0=Sunday).

%x

Equivalent to "%d/%m/%Y" ("%m/%d/%Y" US)

%X

Equivalent to "%H:%M:%S"

%Y

Full year, including century ("1989")

%y

Year of century ("89")

%z

Equivalent to "%d/%m/%y" ("%m/%d/%y" US) (no century)

%Z

Time zone ("PST")

%%

The "%" character

'-' (hyphen) do not pad the field (i.e. "%-d") '_' (underscore) pad the field with spaces (i.e. "% m")

$ date Tue May 9 21:09:07 EDT 2006

$ yest 05/08/2006

$ SARFILE=/var/adm/sa/sa`yest -14 %d` $ echo $SARFILE /var/adm/sa/sa25

$ COUNT=+4 $ yest "The date is:\n\tThe %dth day of %B, %Y" 1988-12-28 $COUNT The date is: The 1st day of January, 1989

$ yest -3h 05/09/2006-18:09