cvs annotate

Shows listing of who modified each line, when it was modified and in which version the last modification first appeared. Example:

 $ cvs annotate hello.py
Annotations for hello.py
***************
1.1          (dyork    10-Jun-01): #!/usr/bin/env python
1.1          (dyork    10-Jun-01): #
1.1          (dyork    10-Jun-01): # This is a very simple python program.
1.1          (dyork    10-Jun-01): #
1.1          (dyork    10-Jun-01): 
1.3          (dyork    11-Jun-01): string = "Hello, again!  Welcome to my world."
1.1          (dyork    10-Jun-01): 
1.1          (dyork    10-Jun-01): print string
1.4          (fred     11-Jun-01): count = 0
1.1          (dyork    10-Jun-01): 
1.1          (dyork    10-Jun-01): for letter in string:
1.4          (fred     11-Jun-01):     print " " * count, letter
1.4          (fred     11-Jun-01):     count = count + 1
1.1          (dyork    10-Jun-01): 
$ 

Can be used with -r or -D to look at file at a certain revision/tag or date.