Sending Text to the Browser
No useful program can be useful in a vacuum. The functions described in this chapter are concerned with I/O (Input and Output), whether it's to the browser, files, or across a network. Some of them perform very specialized duties such as manipulating files. Others are simply for debugging or reporting information about the environment.
If you are experienced in traditional application development, you may be challenged by the unique characteristics of a stateless operating environment. Your script can't sit in a loop and get input from the user until the quit button ...