Programming :: Comparing Two Files ?

I have two files

Code:

we have to consider here $5 , $6 , $7 for our search

file2.txt

Code:

Here we should take only $2 for comparison. As you can most of the $2 field records has value and some do not have value.

Question:I want to take the fields $5 , $6 , $7 from file 1 and compare it with $2 field from file 2. and the rsult should be like this:

Code:

The final output will look like this

Actual file1.txt (before running the code)

Code:

FIle1.txt after running the above said condition

Code:

So the field $5 , $6 , $7 should get replaced from the matched valued of $1(file1)