Shell Programming and Scripting

Hi all,

I currently have a UNIX file maintenance script that runs daily as a cron job.

Now I want to change the script and create functions/sub inside it that runs on a weekly or monthly basis.

To run all the scripts' daily maintenance, I want to schedule it in cron as simply maint.sh when it runs all of its daily maintenance. To run its weekly maintenance functions/subs, I schedule it as maint.sh weekly=6 where 6 is saturday. To run its monthly task, I schedule it as maint.sh monthly=15, i.e. every 15th of the month. Not sure whether I can do monthly=eom where eom is to run functions/sub for every end of the month.

At the moment, am playing around with the weekly functions/sub and what I've done so far is to do something like below

Code:

 
day_of_the_week=`date '+%A' | tr "[:upper:]" "[:lower:]"`
day_of_the_week_n=""
date_of_the_month=`date '+%d'`
 
case "${day_of_the_week}" in
   "monday" )
      day_of_the_week_n=1 ;;
   "tuesday" )
      day_of_the_week_n=2 ;;
   "wednesday" )
      day_of_the_week_n=3 ;;
   "thursday" )
      day_of_the_week_n=4 ;;
   "friday" )
      day_of_the_week_n=5 ;;
   "saturday" )
      day_of_the_week_n=6 ;;
   "sunday" )
      day_of_the_week_n=0 ;;
esac

Then I compare the day_of_week_n variable with the value of the command below:

Code:

 
echo ${1} | grep "weekly" | cut -f2 -d=

And then I use if-then-else to compare if current day of the week matches, then it will run the weekly functions/sub. So weekly=6 will run saturday's functons/sub, weekly=1 will run monday's functions/sub and so on.

Am wanting to know if there is a better way of parsing for the day of the week besides what am doing at the moment which is using case and then doing if-then-else to check for the day of the week.

For the monthly functions/sub, I uses the value of the one below and uses if-then-else again to compare it when monthly=15.

Code:

 
date_of_the_month=`date '+%d'`

Perhaps anyone can advice if there is any way I can check for end of month?

Any advice much appreciated. Thanks in advance.

Here's a simple way to determine if it's the last day of the month.

Code:

#!/bin/ksh

dim=( 00 31 28 31 30 31 30 31 31 30 31 30 31 )  # one based, days in month

# capture information from date: day or week, month, day, year
dinfo=( $(date "+%w %m %d %Y" ) )
dow=${dinfo[0]}
mon=${dinfo[1]}
dnum=${dinfo[2]}
year=${dinfo[3]}

# the previous 5 lines can be reduced to this if you are using ksh
#date "+%w %m %d %Y" | read dow mon dnum year


if (( year % 4 == 0  &&  (year / 100 != 0 || year/400 == 0) ))  # adjust if leapyear
then
    (( dim[2]++ ))
fi

eom=0                       # default to end of month false
if (( dnum == dim[mon] ))
then
    eom=1
fi

if (( eom ))    # end of month check
then
    echo "it's end of month"
else
    echo "it's not end of month"
fi

if (( dow == 0 ))
then
    echo "it's Sunday"
else
    echo "it's not Sunday"
fi

You can also assign the day of week as a number directly from the output of the date command -- you don't need to translate the name into a number.