Shell Programming and Scripting

hi,
i am parsing a file, in that searching for lines those contains "$threadNo.Received message:" , if that line contains the required fields write them into a separate file other wise ignore them.
i am using the following code,but it is printing all the lines , i dont want to rpint , please help


cat $file | grep -i "$threadNo.Received message:"
if [ $? -eq 0 ]
then
cat $file | grep -i "$threadNo.Received message:" > $threadNo.File
else
echo "The line does not contain the required fields"
fi

If I understand you, the lines you want to extract must contain "?????.Received message:" How about?

Code:

if grep -f "${threadNo}.Received message:" > $threadNo.File 
then
   cat $threadNo.File
else
   echo "The line does not contain the required fields"
fi

hi otheus,
i made the problem complicated, just i need to delete a line that deos not contain the particular pattern like "17 Received message"

please help

grep -v -f "17 Received message" filename