Requirement
I have tst1.txt and tst2.txt 
tst1.txt have data as below
Note: ABCD & EFGH are segments in below data
ABCD
     TEST1
     TEST2
     TEST3

EFGH 
     TEST1
     TEST2
     TEST3

tst2.txt have data as below
ABCD
     TEST1
     TEST2
     TEST3
EFGH 
     TEST1
     TEST2
     TEST3
     TEST4
     TEST5

Now diff between two files is in tst2.txt the last two rows "TEST4", "TEST5"
I need to have a script which gives output as below
Diff between two files is from segment
EFGH
     TEST4
     TEST5