ksh get quarter start end dates

Question

I am writing a shell script, and need to calculate the first and last days of a quarter from the current date. This is for use in Ingres 10 SQL statements triggered from within the script. The Ingres runs on a Solaris server with ksh.

So, if today is 31/01/17, I would want to calculate the following

1. the first date of the current quarter (01/01/17)
2. the last date of the current quarter (31/03/17). It would be OK here to return an exclusive to date if necessary (i.e. 01/04/17)
3. the first date of the previous quarter (01/10/16)
4. the last date of the previous quarter (31/12/16). An exclusive-to result of 01/01/17 would also be OK.

Can anyone please help? I've seen questions related to getting the quarter number but that's not really helping.

I've tried the following but its not working as the variables are not being populated in the case statement

CURR_MONTH=`date +%m`
echo "Current month num = $CURR_MONTH"

CURR_YEAR=`date +%Y`
echo "Current year = $CURR_YEAR"

let "LAST_YEAR = $CURR_YEAR - 1"
echo "Last year = $LAST_YEAR"


case $CURR_MONTH in
05) CURR_Q_FROM = 01.04.${CURR_YEAR}
CURR_Q_TO = "30.06.${CURR_YEAR}"
PREV_Q_FROM = "01.01.${CURR_YEAR}"
PREV_Q_TO = "31.03.${CURR_YEAR}" ;;
esac

echo "Current Q From = $CURR_Q_FROM"
echo "Current Q To = $CURR_Q_TO"
echo "Prev Q From = $PREV_Q_FROM"
echo "Prev Q To = $PREV_Q_TO"

I get the following output

Current month num = 05
Current year = 2017
Last year = 2016
Month to be extracted = April 2017
./stats_report_monthly.sh[85]: CURR_Q_FROM:  not found
./stats_report_monthly.sh[86]: CURR_Q_TO:  not found
./stats_report_monthly.sh[87]: PREV_Q_FROM:  not found
./stats_report_monthly.sh[88]: PREV_Q_TO:  not found
Current Q From =
Current Q To =
Prev Q From =
Prev Q To =

Answer 1

With ksh93 (also /bin/sh on Solaris 11):

#! /usr/bin/ksh -
eval "$(printf '%(y=%Y m=%-m)T')"
first=$(printf '%(%F)T' "$y-$(((m-1)/3*3+1))-1")
last=$(printf '%(%F)T' "$first next 2 months last day")
echo "$first $last"

first2=$(printf '%(%F)T' "$first last 3 months")
last2=$(printf '%(%F)T' "$first2 next 2 months last day")
echo "$first2 $last2"

Example:

$ ./quarter
2017-04-01 2017-06-30
2017-01-01 2017-03-31
$ faketime 2017-01-31 ./quarter
2017-01-01 2017-03-31
2016-10-01 2016-12-31

Using your approach, that would be:

eval "$(date +'y=%Y m=%m')"
case $m in
  (0[1-3])
     echo "$y-01-01 $y-03-31"
     echo "$((y-1))-10-01 $((y-1))-12-31";;
  (0[4-6])
     echo "$y-04-01 $y-06-30"
     echo "$y-01-01 $y-03-31";;
  (0[7-9])
     echo "$y-07-01 $y-09-30"
     echo "$y-04-01 $y-06-30";;
  (*)
     echo "$y-10-01 $y-12-31"
     echo "$y-07-01 $y-09-30"
esac

In any case, note that the syntax of variable assignments in Bourne-like shells is:

var=value

No space on either side of =.