Optimal commands in robots.txt

Could anyone please suggest what should be minimum commands present in robots.txt so that site is well crawled by search engines.

1. Having NO robots.txt is good or bad?
2. If its good to have rotobts.txt, what should be minimal standard commands in it (I dont need anything specific)

Thanks In Advance!

 

robots.txt is useful when you disallow access on the site for some of the robots ;-) However, You can even put an empty file on a server.

For more info visit http://www.robotstxt.org/wc/robots.html

 

For a standard robots.txt file, use this:

User-agent: *
Disallow: 

Code (markup):

Create this in a text editor like Notepad and save as ASCII/ANSI format (plain text rather than unicode or anything else).