Shell Programming and Scripting

if [ $(date +%d) -eq $(cal | awk ' NF == 7 { day=$7 } END { print day } ') ]
then
   echo "Today is last Saturday"
fi

S M Tu W Th F S
1 2

{ print day }

#! /bin/sh
#
# Script to fnind the last or first given day of the current month
## 
# Andre Kokot 9 Nov 2006
# Started the code
# 
# #####################################################################

Usage() {
echo "`basename $0` -d [0-6] -o [f|l] "
echo
echo "\t-d [0-6] (Sunday-Saturday), Day of Week"
echo "\t-o [f|l] (First|Last),      Day of Month"
echo

exit 99
return
}
# ####################################################################

Defaults() {

tmpfile=/tmp/calfile
TODAY=`date +%d | sed s.^0..`

#Create a calander in file to process
cal `date +%m" "%Y` | grep -v -e '^$' -e `date +%B` -e  Tu > $tmpfile

return
}

# ####################################################################
ConfDay() {

case $2 in
 [0-6]) : ;;
   *) echo "Invalid day"
      Usage ;;
esac

case $1 in
  l) nday=`expr $2 + 1`
   ;;
  f) set -A farry 7 6 5 4 3 2 1
     nday=${farry[$2]}
   ;;
esac


return
}
# ####################################################################
Getinfo() {
#1 - Option
#2 - Date arry from cal

set -A dtarry $2

case $1 in
   f) if [ ${#dtarry[*]} -ge $nday ]
		 then
         nday=`expr ${#dtarry[*]} - $nday`
         dtfound=${dtarry[${nday}]}
        else
         Find $1 2   # Need the previous week details
      fi
      ;;
   l) if [ ${#dtarry[*]} -ge $nday ]      # Its with in current range
       then
         dtfound=${dtarry[${day}]}
       else
         Find $1 2   # Need the previous week details
      fi
      ;;
esac

ShowResult $dtfound

return
}
# ####################################################################
ShowResult() {

case $1 in
   $TODAY)
      EOM=0 ;;  # This means YES
   *)
      EOM=1 ;;  # This means NO
esac

echo "$EOM"
exit $EOM

return
}
# ####################################################################
Find() {

#1 - Option
#2 - head value

case $1 in 
  l) daterow="`cat $tmpfile | sort -r | head -$2 | tail -1`"
     ;;
  f) daterow="`cat $tmpfile | head -$2 | tail -1`"
     ;;
  *) echo
     echo "Can only find (l)ast or (f)irst day"
     echo 
     Usage ;;
esac

Getinfo $1 "$daterow"

return
}
# ####################################################################
# MAIN - STARTS HERE

while getopts d:o: opt
do
  case $opt in
     d) day=$OPTARG
        #day=`echo $OPTARG | tr -d \"[A-z]\"`
		 #if [ $day -gt 6 ] || [ -z "$day" ]
		 #  then
		 #     Usage
		 #fi
		 ;;
     o) option=$OPTARG ;;
     *) Usage ;;
  esac
done

# Set defaults
Defaults
ConfDay $option $day
Find $option 1   # First pass

#
## Now we know what the last day of the month is,
## need to verify if its today
#