How to write the robots file

I want to disabled search engine to crawl the page such as

/a_xxxxxx.html
/b_xxxxxx.html

This is the content of my robots file .Does it right?
User-agent: *
Disallow: /a_*.html
Disallow: /b_*.html

 

This example disallows all Web Spiders for the entire site:
# Make changes for all web spiders
User-agent: *
Disallow: /

 

I just disallow the page begining with 'a_' or 'b_' .
Not all page.

 

Please help me/

 

Are you planning to block any directory like this example

User-agent: *
Disallow: /administrator/
Disallow: /cache/
Disallow: /images/

 

Hi.. Go through the website robotstxt.org/robotstxt.html that will help u out.

 

here is the code you you need to create

User-agent: *
Disallow: /a_xxxxxx.html
Disallow: /b_xxxxxx.html