Re: [foxboro] Calculating yesterday for shell scripts on SOTM and P91

Thanks Edwin!
Your google fu is strong :)  I looked, but found too many references and
didn't get to the meaningful bits.  Much appreciated!

OK, what I was missing was that the GST in TZ=GST+24 is just a label and
does not have a real meaning in that statement.  So, my TZ=GST+15 to get
yesterday is the same as TZ=any+15.

Cheers,

Kevin

On Tue, May 19, 2009 at 10:15 PM, Edwin Nasol <enasol@xxxxxxxxxxxxxx> wrote:

> Kevin,
>
> This 1st URL,
> http://www.informatik.uni-frankfurt.de/doc/man/hpux/environ.5.html
> describes the TZ definition syntax (extract below):
>
> >>>quoted text start>>>
>
>      TZ          TZ sets time zone information.  TZ can be set using the
>                  format:
>
>                          [:]STDoffset[DST[offset][,rule]]
>
>                     where:
>
>                        STD and DST Three or more bytes that designate the
>                                    standard time zone (STD) and summer (or
>                                    daylight-savings) time zone (DST) STD is
>                                    required.  If DST is not specified,
>                                    summer time does not apply in this
>                                    locale.
>
>                        offset      offset is the value that must be added
>                                    to local time to arrive at Coordinated
>                                    Universal Time (UTC).  Offset is of the
>                                    form :
>
>                                         hh[:mm[:ss]]
>
>                                    Hour (hh) is any value from 0 through
>                                    23.  The optional minutes (mm) and
>                                    seconds (ss) fields are a value from 0
>                                    through 59.  The hour field is required.
>                                    If offset is preceded by a -, the time
>                                    zone is east of the Prime Meridian.  A +
>                                    preceding offset indicates that the time
>                                    zone is west of the Prime Meridian.  The
>                                    default case is west of the Prime
>                                    Meridian.
>
> <<<quoted text end<<<
>
> This 2nd URL,
> http://unix.derkeiler.com/Mailing-Lists/AIX-L/2003-12/0110.html
> describes the "[the TZ trick]" to get tomorrow's date, in the same way you
> are
> getting yesterday's. There is an interesting comment though:
>
> >>>quoted text start>>>
>
> It doesn't always give yestday's date.
> eg. TZ=XXX-24 gives tomorrow's (not yesterday) date/time if you are in
> England.
> If you want your own time zone, replace the [-][0-9]* with the value +24
> hours (yes, a "+" value)
> eg. if EST5EDT, use TZ=xxx29
> eg. if JST-9, use TZ=xxx15
>
> <<<quoted text end<<<
>
> The 3rd URL,
> http://unix.derkeiler.com/Newsgroups/comp.unix.shell/2006-02/msg00814.html
> puts it all together:
>
> >>>quoted text start>>>
>
> Hi,
> Can anyone please tell me what 'aaa' in TZ=aaa24 date +%Y%m%d
> stands for. I have searched the unix man pages but not able to get its
> meaning.
>
> [...]
>
> as long as you use the format TZ=<string><offset>
>
> <string> will just be some descriptive text that you chose to
> describe that rule. As long as you specify an offset (it could
> be even more complicated like having two offsets for day light
> saving time, and rules to tell when to switch to DST), then the
> <string> is not used to define the rules (aaa will not refer to
> any description file in /usr/share/zoneinfo contrary to another
> contributor said), it will just be used in date +%Z.
>
> So, TZ=aaa24 is a tab zone called "aaa" that is defined as being
> offset by 24 wrt Universal time (GMT, UTC).
>
> <<<quoted text end<<<
>
> The statement, yesterday=`TZ=xxx15 date "+%Y-%m-%d"`, will do for you
> nicely.
>
> Hope this helps,
> Edwin Nasol
>
>
>
>
>
> _______________________________________________________________________
> This mailing list is neither sponsored nor endorsed by Invensys Process
> Systems (formerly The Foxboro Company). Use the info you obtain here at
> your own risks. Read http://www.thecassandraproject.org/disclaimer.html
>
> foxboro mailing list:             http://www.freelists.org/list/foxboro
> to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
> to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave
>
>


 
 
_______________________________________________________________________
This mailing list is neither sponsored nor endorsed by Invensys Process
Systems (formerly The Foxboro Company). Use the info you obtain here at
your own risks. Read http://www.thecassandraproject.org/disclaimer.html
 
foxboro mailing list:             http://www.freelists.org/list/foxboro
to subscribe:         mailto:foxboro-request@xxxxxxxxxxxxx?subject=join
to unsubscribe:      mailto:foxboro-request@xxxxxxxxxxxxx?subject=leave

Other related posts: