UNIX for Advanced & Expert Users

can anyone please suggest me some ideas for writing a korn shell script which will go back to 36 days from current day and print each day (incremented by 1) in the format yyyy-mm-dd until the current day.

Thanks
Mark

There are a number of articles regarding date arithmetic on the site:

try https://www.unix.com/answers-frequent...rithmetic.html

from the FAQs - you may find your answer (or something close) in there.

What have you tried so far ? Post any code you may have and you're likely to get some good assistance.

Cheers

This is the code i have so far. for now the loop is for 5 days. later i wish to update it to 36 days.

Code:

#!/bin/ksh

set -x
i=1
 while [ $i -le 5 ]; do
_day=`date +%Y%m%d`
newday=`expr $_day - $i`
echo $newday
echo "================================="
i=`expr $i + 1`
echo $i
done

but i have a problem, expr 20091001 - 2 then i see this newday=20090999

Can anyone please suggest me.

Thanks
Mark

The previously suggested FAQ link and the forum 'Search' capability should give you a head start.
Have you looked into those?

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heres a simple way:-

Code:

#!/bin/ksh
set -x
i=1
 while [ $i -le 5 ]; do
date -d "`date +%Y`-01-01 +$(( `date +"%j"` - $i ))days" +%Y-%m-%d
i=`expr $i + 1`
echo $i
done

i have used a simple trick to convet the current calender date into julian date, substract it by 1, and convert back it to the calendar date

one another way,

Code:

date --date="36 days ago"  +"%Y-%m-%d"

Use a variable and reduce the 36 upto required num, and proceed.


As, I have no experience in writing korn shell script !!! Write the above suggested by your own.

the geek -

Your method is good as long as the OP has GNU date installed on his machine.

You can also try perl.

Code:

#!/bin/ksh
# will run on Solaris with the date/time format %s problem.

end=$( perl -e ' print time;' )
start=$(( end - ( 86400 * 36) ))  # 36 days in the past
while [[  $end -ge $start  ]]
do
     perl -e 'use POSIX qw(strftime);
              $mt = strftime "%a %b %e %H:%M:%S %Y", localtime($ARGV[0]); 
              print $mt,"\n";' $start
     start=$(( $start + 86400 ))
done