topic Re: Info on timestamp in Operating System - Linux

Info on timestamp

Karthik_sg — Mon, 20 Aug 2007 05:02:59 GMT

hi guys,
Can any body tell me how to subtract the current timestamp - 3minutes.
Thanks in advance.

Re: Info on timestamp

Danny Petterson - DK — Mon, 20 Aug 2007 05:11:55 GMT

perl -e 'print scalar localtime(time-180)'

...where "180" is the seconds for three minutes.

Yours
Danny Petterson

Re: Info on timestamp

Karthik_sg — Mon, 20 Aug 2007 05:32:24 GMT

Can u tel me in shell scripting pls

Re: Info on timestamp

Karthik_sg — Mon, 20 Aug 2007 06:37:29 GMT

And the timestamp is in this format.
2007-07-19 14:29:33
Now How to subtract the 3 minutes tht i had askd earlier.

Re: Info on timestamp

Oviwan — Mon, 20 Aug 2007 07:19:55 GMT

Hey

I suggest you to use perl:
perl -e '@x=localtime(time-3*60);printf"%4d-%02d-%02d %02d:%02d:%02d\n",$x[5]+1900,$x[4]+1,$x[3],$x[2],$x[1],$x[0]'

Regards

p.s. I have assigned points to 4 of 36 responses --> don't forget to assign points, also in your other threads!

Re: Info on timestamp

Stuart Browne — Mon, 20 Aug 2007 08:52:46 GMT

In raw shell, not easily from a timestamp.

You can use 'date -d ""', but you can't do further modifications to it.

If you just wanted the current time 3 minutes ago, you could have used 'date -d "3 minutes ago"', but this doesn't work stacked onto another -d.

Unfortunately, 'date -d' doesn't understand the Epoch form of time, i.e. 'date -d 1184819193'. If it did, you could stack some date's, but it doesn't.

So, use the funky perl method. You can $() it in a subshell *shrug*.

Re: Info on timestamp

Karthik_sg — Thu, 23 Aug 2007 01:28:13 GMT

And can u pls explain this

perl -e '@x=localtime(time-3*60);printf"%4d-%02d-%02d %02d:%02d:%02d\n",$x[5]+1900,$x[4]+1,$x[3],$x[2],$x[1],$x[0]'

with respect to

2007-07-19 14:29:33

i have assigned points and thanks.

Re: Info on timestamp

Stuart Browne — Thu, 23 Aug 2007 01:37:22 GMT

Wait, I'm confused. I think I mis-read your original post.

Do you want to take 3 minutes away from the current time, or from a pre-defined time?

If from the current time, you can use either the perl method above, or:

date -d '3 minutes ago' +'%Y-%m-%d %H:%M:%S'

But this all depends on how and where you want to use it.

For instance, if you're wanting to do this calculation to use in an SQL query, it's easier to do it *IN* SQL. The MySQL syntax would be simply:

SELECT DATE_SUB(NOW(), INTERVAL 3 MINUTE);

In other SQL's, there can be slightly different syntax.

So, can you tell us where you want to use this? Perhaps then we can give you a better answer.

Re: Info on timestamp

Karthik_sg — Thu, 23 Aug 2007 03:35:27 GMT

I am using it in mysql.the difference is used in a script where we generate alerts.i.e, if the time is same for the last 3 minutes then we are suppose to notify via the script.thanks,i wil try try this and let u know

Re: Info on timestamp

Karthik_sg — Thu, 23 Aug 2007 05:09:39 GMT

hi The query u had sent doesnt work in mysql .u have any idea how it goes in mysql

Re: Info on timestamp

Stuart Browne — Thu, 23 Aug 2007 16:58:03 GMT

.. How can you not get that to work?

SELECT data_field FROM table WHERE time_field > DATE_SUB(NOW(), INTERVAL 3 MINUTE);

This assumes that the 'time_field' is in a date/time/datetime/timestamp format.

If it's in epoch time (a flat integer), then use 'UNIX_TIMESTAMP() - 180' instead.