I have a large program in mathematica, and generate many outputs. However, I don't want those outputs to be visible in my program and I want to save the outputs in text or any other format. Moreover I also want to call any of the outputs and perform some specific operations on it (plotting, squaring etc.) Please guide me in this respect.
You need to use the Export function. If you want the output suppressed, use semicolons. See the help file on Export for more.
(I don't know what else to say..)