Thursday, February 21, 2013

How to Write a robots.txt File

It's easy to learn how to write a valid robots.txt file that search engine spiders will follow and clearly understand. This how to takes you through the steps.
Difficulty: Average
Time Required: 5 minutes

Here's How:

  1. In a text editor, open a file named robots.txt. Note that the name must be all lower case, even if your Web pages are hosted on a Windows Web server. You'll need to save this file to the root of your Web server. For example:
    http://webdesign.about.com/robots.txt
  2. The format of the robots.txt file is
    User-agent: robot Disallow: files or directories
  3. You can use wildcards to indicate all robots, or all robots of a certain type. For example:
    To specify all robots:
    User-agent: *
    To specify all robots that start with the letter A:
    User-agent: A*
  4. The disallow lines can specify files or directories:
    Don't allow robots to view any files on the site:
    Disallow: /
    Don't allow robots to view the index.html file
    Disallow: /index.html
  5. If you leave the Disallow blank, that means that all files can be retrieved, for example, you might want the Googlebot to see everything on your site:
    User-agent: Googlebot Disallow:
  6. If you disallow a directory, then all files below it will be disallowed as well.
    Disallow: /norobots/
  7. You can also use multiple Disallows for one User-agent, to deny access to multiple areas:
    User-agent: * Disallow: /cgi-bin/ Disallow: /images/
  8. You can include comments in your robots.txt file, by putting a pound-sign (#) at the front of the line to be commented:
    # Allow Googlebot anywhere User-agent: Googlebot Disallow:
  9. Robots follow the rules in order. For example, if you set googlebot specifically in one of your first directives, it will then ignore a directive lower down that is set to a wildcard.
    # Allow Googlebot anywhere User-agent: Googlebot Disallow:  # Allow no other bots on the site User-agent: * Disallow: /

Tips:

  1. Find robot User-agent names in your Web log
  2. Always follow the capitalization of the agent names and the file and directories. If you disallow /IMAGES the robots will spider your /images folder
  3. Put your most specific directives first, and your more inclusive ones (with wildcards) last

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