UNIX for Dummies Questions & Answers

#!/bin/ksh
count_prev=0
count=0
mask=false
while read line
do
  if [ `echo $line | grep -cw HOME` -eq 1 ]; then
    mask=true
    count_l=0
    count_r=0
    count=0
  fi  
  let count_l=count_l+`echo $line | grep -c '('`
  let count_r=count_r+`echo $line | grep -c ')'`
  count=$(expr $count_l - $count_r)
  if [ $mask == "false" ]; then
    echo $line
  elif [ $count_prev -eq 0 -a $count -eq 0 ]; then
    echo $line
    mask=false
  fi  
  count_prev=$count
done < in_file