NOw that the above problem is solved , I am stuck up with another grep issue,

I replaced the cat like below:-
cat $FileName | grep -v "#" | sed -e 's/ / /g' | awk '{print '$awk_filter'}' | grep -w $Filter_String

this works only if Filter_string has one word , if it has two words like "yes dr" then it gives
grep: 0652-033 Cannot open dr".

Here the grep is not taking the entire content of the $Filter_String to search ,rather it tries to search to search yes in the file dr. How we avoid this.