Are there semantic rules in shell scripts covering whether multiple
usages of "date" return consistent values (as there are for date/time
functions within a single REXX statement)? If not, any script with
multiple "date" commands like the "long" example given will potentially
fail if the midnight boundary is crossed during execution as the Y, m,
and d values returned may increment from one invocation to the next and
not all of the values examined are guaranteed to be consistent with a
single date. For example, if consistency is not guaranteed, the test
for day "01" may run while the date is last day of month, and subsequent
code which presumes "not day 01" may run after the date has actually
changed to day "01".
The example also demonstrates why one really needs some simple command
option to do date offsets, as there is no way one can be certain code of
this complexity has no syntactic errors just by a visual inspection, and
I suspect shell script execution wouldn't necessarily warn of all errors
in parts of the statement that are not actually executed during a
particular invocation.
JC Ewing
On 03/14/2013 03:16 PM, Rafal Hanzel ZETO Katowice wrote:
Yes, You're right.
In this situation you need pretty simple script or something like
this: long "single command" tested on my linux
if [ `date +%d` -ne 01 ]; then echo "`date +%Y%m%d` - 1" | bc; elif [
`date +%m` -ne 01 ]; then echo $(echo $(date +%Y) $(echo $(date +%m) )
$(cal $(echo "$(date +%m) -1" | bc) $(date +%Y) | tr -d '\n' | tr -d
' ' | tail -c 2) | tr -d ' ') - 100 | bc; else echo $(echo $(date +%Y)
12 $(cal 12 $(echo "$(date +%Y) -1" |bc ) | tr -d '\n' | tr -d ' ' |
tail -c 2) | tr -d ' ') - 10000 | bc; fi
I can't try this in USS now, but I hope it works
---
Pozdrawiam/Best regards,
Rafal Hanzel
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Treść tej informacji może być poufna, w związku z czym powinna trafić
bezpośrednio do rąk adresata. Jakiekolwiek jej ujawnianie,
rozpowszechnianie, bądź kopiowanie jest zabronione. W przypadku
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W dniu 14.03.2013 14:32, Uwe Oswald napisał(a):
Thx perfect, thats exactly what I need. But I'm afraid this doesn’t
work for the first of a month for example 20130401 will then be
20130400 or I'm wrong?
-----Ursprüngliche Nachricht-----
Von: IBM Mainframe Discussion List [mailto:[email protected]]
Im Auftrag von Rafal Hanzel ZETO Katowice
Gesendet: Donnerstag, 14. März 2013 13:23
An: [email protected]
Betreff: Re: USS "date" command, subtract one day
Maybe something like that, will help you:
echo "`date +%Y%m%d` - 1" | bc
---
Pozdrawiam/Best regards,
Rafal Hanzel
W dniu 14.03.2013 12:54, Uwe Oswald napisał(a):
Hi,
I dont know if this is the right forum but I hope someone could help
anyway. I want to subtract "one day" from the actual date with one USS
unix command.
The actual date I get via "date +%Y%m%d" (for example 20130314), but
"date +%Y%m%d-1" or "...yesterday" don’t work. I have tried everything
without success. Does anybody have a tip for me? It must be achieved
within one command not more.
Thx
Uwe
...
--
Joel C. Ewing, Bentonville, AR [email protected]
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