For example, if I wanted to know all the methods and properties, methods and events available on the base http class, I could type something like http()? and it would return
http.createServer([requestListener])
http.createClient([port], [host])
For any of the require modules like http, just enter the name at the console prompt:
> http
You get a little tidier presentation if you enter http. at the prompt and then press Tab.
Both will tell you names of the available functions, but not their parameters. You need to check the docs for that.