Shell Programming and Scripting

#!/bin/ksh
set -A daynames Sun Mon Tues Wed Thur Fri Sat

dow() # convert date to dow
{
  # $1 month  $2 day $3 year 
    
  cal $1 $3 | sed '/^$/d' |\
  awk 'BEGIN {getline; getline}
      { if(days==0) {offset= 7 - NF} for(i=0; i<NF; i++) {days++}
      } END { print offset, days }' | read offset days
  typeset -i day=$2
  if [[ $day -le $days && $day -gt 0 ]]  
  then
  	 echo ${daynames[ $(( (($day + offset) % 7) -1 )) ]}
  else 
     echo "Invalid parameter" 
  fi
}

dow 11 02 2008 
dow 01 01 1999

cal 11 2008 | \
awk -v v=8 '
NR==2{
   for(i=1;i<=NF;i++) a[i]=$i
}
NR>2{
   for(i=1;i<=NF;i++)
        {
        if($i==v) d=a[i]
        }
}
END{
print d
}'