[CentOS] Inquiry:How to compare two files but not in line-by-line basis?

Wed Dec 2 11:23:56 UTC 2009
John Doe <jdmls at yahoo.com>

From: hadi motamedi <motamedi24 at gmail.com>
>Sorry . I tried for "#diff -y" but its output seems to have a comparison between the two files in line-by-line basis . As you mentioned , if the row#1 in file1 is in match with say row#5 in file2 I want it not to be considered as a difference. But the the output shows it as if it is being considered as a difference. Please correct me .

Could you be more precise when you say "compare"...?
By example, to get matching lines, you could:

  cat $FILE1 $FILE2 | sort | uniq -c | ...

You'd get each line preceded by the number of occurence; then grep what you want...