dateadd

English Programming/Scripting
#1

I want to make a dateadd with the date command but this only works with the current date, not with a customized date.
Everything goes fine when I tray to a add single days to a date:


date '+%Y-%m-%d %H:%M:%S' --date=' +2 days'

returning this output


2008-06-25 12:45:21

or


date '+%Y-%m-%d %H:%M:%S' --date='2007-10-10 00:10:00 +1 days'

output


2007-10-11 00:10:00

even when I add a time to the current date


date '+%Y-%m-%d %H:%M:%S' --date=' +1 minutes'

BUT

if I add a day greatest than 1 (one) to a date that is not the current one (today), does not work


date '+%Y-%m-%d %H:%M:%S' --date='2007-10-10 00:10:00 +5 days'

output


2007-10-11 00:10:00

the same thing happens with a time add


date '+%Y-%m-%d %H:%M:%S' --date='2007-10-10 00:10:00 +5 minutes'

output


2007-10-09 20:06:00

what is wrong with this?

#2

What is wromg with this? IMHO it is simply wrong!

Look it these:

henk@boven:~> date '+%Y-%m-%d %H:%M:%S' --date='2007-10-10 00:10:00 +5 minutes'
2007-10-10 02:06:00
henk@boven:~> TZ=UTC0 date '+%Y-%m-%d %H:%M:%S' --date='2007-10-10 00:10:00 +5 minutes'
2007-10-10 00:06:00
henk@boven:~>

Doing this in timezone UTC0 as advised somewhere in info date .

When you think this is broken, I agree (does not help you very much :mad: ).

#3

:s

Is there a way to do the same in C or C++?

#4

As I read info date, the semantics you want are simply not supported. In your examples it’s treating the +N as some weird timezone. Relative dates are only relative to current time, not to a time you specify. You’ll have to do it some other way.

#5

The carbonbased lifeform ken yap inspired
opensuse.org.help.programming-scripting with:
>
> As I read info date, the semantics you want are simply not supported. In
> your examples it’s treating the +N as some weird timezone. Relative
> dates are only relative to current time, not to a time you specify.
> You’ll have to do it some other way.

!/usr/bin/python
from datetime import *

Now = datetime.now()
Interval = timedelta(seconds=0, minutes=0, hours=0, days=2)
DateAdd = Now + Interval

>>> print Now
2008-06-24 00:54:28.091262

>>> print Interval
2 days, 0:00:00

>>> print DateAdd
2008-06-26 00:54:28.091262

Theo

theo at van-werkhoven.nl ICQ:277217131 SuSE Linux
linuxcounter.org: 99872 Jabber:muadib at jabber.xs4all.nl AMD XP3000+ 1024MB
“ik heb niets tegen Microsoft, ik heb iets tegen
de uitwassen van Microsoft”

#6

And if you really want to do it all in shell and using date, you could output the first operand as seconds past epoch (%s formatter), add the required number of seconds to it, using expr or bash $(()), then reconvert to your required format using the @secsfromepoch input format.

#7

This kind of works


~> bash --version
GNU bash, version 3.2.25(1)-release (i586-suse-linux-gnu)
Copyright (C) 2005 Free Software Foundation, Inc.
~> date --version
date (GNU coreutils) 6.9
Copyright (C) 2007 Free Software Foundation, Inc.
...
~> date --date='tomorrow + 5 minutes 2004-02-28 10:00:00' +'%F %H:%M:%S'
2004-02-29 10:05:00
~> date --date='+ 1 day + 5 minutes 2004-02-28 10:00:00' +'%F %H:%M:%S'
2004-02-29 10:05:00
~> date --date='+ 2 days + 5 minutes 2004-02-28 10:00:00' +'%F %H:%M:%S'
2004-03-01 10:05:00
~> date --date='+ 11 days + 55 minutes + 2 seconds 2004-02-28 10:00:00' +'%F %H:%M:%S'
2004-03-10 10:55:02
~> date --date='- 2 weeks - 5 minutes - 59 seconds 2004-02-28 10:00:00' +'%F %H:%M:%S'
2004-02-14 09:54:01
#8

Just to add an example to previous post
~> date -r 1337466.asx +’%F %H:%M:%S’
2008-06-24 09:59:54
~> x=$(date -r 1337466.asx +’%F %H:%M:%S’); date --date=’+ 5 days + 1 hour ‘"$x" +’%F %H:%M:%S’
2008-06-29 10:59:54

#9

Thank you very much to all of you :slight_smile:
now it works!