First and last day of the month 1

[columb]

Date calculations are always a pain!

I'm writing some availability reports.
this_month.ksh is easy - period start is 01/$(date +%m/%y) and period end is $(date +%d/%m/%y)

However, I'm now writing last_month.ksh. Period start is relatively easy - something along the lines of

typeset -Z 2 LAST_MONTH=$(date +%m)
((LAST_MONTH -= 1))
PERIOD_START=01/$LAST_MONTH/$(date +%y)

Ok, I know I need to allow for January but that's not the problem.

Has anyone any ideas of how to generate period end? The two options I'm looking at are some sort of lookup table (a kop out!) or to use PHV's date calculatore (see FAQ822-4802) and loop backwards one day at a time untill I hit last month i.e. in pseudo code

OFFSET=24
while TRUE
do
  calc date from offset
  if month = current month - 1 end
  OFFSET += 24
done

but that's a bit clumsy and slow.

Has anyone any ideas?

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Columb Healy

 

[Mike042]

I am unsure what defines the 'period end' in each previous month, but if it is the last day (date) of the month, then try (in Korn shell):
lastdayinfeb=$(echo $(cal 02 2007) | awk '{print $NF}')

which should produce the number 28

I hope that helps.

Mike

 

[columb]

Nice one Mike, that's exactly what I want. Thanks.

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Columb Healy

 

[Chapter11]

another method, if you have gnu's version of date around...

gdate -d "${MONTH}/1/${YEAR} -1 day

 

[kasparov]

It's solved now I know but as a variation on Mike's suggestion you can also do:

cal 02 2007 | xargs | awk '{print $NF}'

Cheers, Chris

 

[p5wizard]

and with just 2 processes:

cal 2 2007|awk '{if (NF) ld=$NF} END{print ld}'


HTH,

p5wizard