A question concerning diff

[Bill Wisner]

Many times, I have wondered privately if there is an answer to this problem;
but have gotten no satisfactory answer. Thus, I take this dumb question to the
net:

Is there a program, command, anything, that will take two files
{
	1. An old text file
	2. A "diff" format file
}
and make the changes listed in #2 on #1 and create file #3, the new text file?
-- 
Bill Wisner
..ihnp4!jack!wolf!billw

Property is theft.				  -- P. J. Proudhon
Property is liberty.				  -- P. J. Proudhon
Property is impossible.				  -- P. J. Proudhon
Consistency is the hobgoblin of small minds. -- Ralph Waldo Emerson