Z:gnu-www-ja-rms-nyu-2001-transcript--28729f-And it's often very useful to/en

And it's often very useful to be able to take pieces out of some existing program, presumably usually large pieces, of course, and then write a certain amount of code of your own, and make a program that does exactly what you need, which would have cost you an arm and a leg to develop, if you had to write it all from scratch, if you couldn't cannibalize large pieces from some existing free software package.