IO REDIRECTION:
Introduction
For those of you’ll who have no idea what Redirection means, let me explain it in a few words. Whenever you run a program you get some output at the shell prompt. In case you don’t want that output to appear in the shell window, you can redirect it elsewhere. you can make the output go into a file…or maybe go directly to the printer.. or you could make it disappear 
This is known as Redirection. Not only can the output of programs be redirected, you can also redirect the input for programs. I shall be explaining all this in detail in this article. Lets ... ... leer más en >>> startwithlinux.wordpress.com
