UNIX for Dummies Questions & Answers

 file1='path to file containing matchable lines';
 file2='path to file to match';
 file3='path to line with replacable lines;
 file4='path to result file'
 l1=`cat $file1|wc -l`;
 l2=`cat $file2|wc -l`
 l3=`cat $file3|wc -l`
 i=0
 j=0
matched=0
rm $file4
touch $file4
 while [ $i -le $l2 ]
 do
    t1=`head -$i $file2|tail -1`
    j=0
    while [ $j -le $l2 ]
    do
     t2=`head -$j $file1|tail -1`
 
     if [ "$t1" = "$t2" ]
          t3='logic for getting string from file3 string'
          t3>file4
          j=`echo $j+1|bc` #to break loop
          matched=1
     fi
    done
    if [ $matched -eq 0 ]
     t1>$file4
    fi
    matched=0
 done