Robots.txt is a text file used by websites to communicate with web crawlers and other automated agents, specifying which areas of the site should not be processed or scanned. It serves as a set of guidelines for search engines and other bots, instructing them on how to interact with the website’s content.
Understanding the Basics
The Robots.txt file is placed in the root directory of a website and is publicly accessible. Its primary purpose is to prevent certain parts of a site from being crawled or indexed, helping site owners control the visibility of specific content in search engine results.
The file consists of a series of directives, each followed by a value. Two common directives are Disallow and Allow. The Disallow directive tells crawlers which paths or directories to avoid while Allow instructing them to access specific areas that might otherwise be restricted.
Disallow Values and Wildcards
Disallow Values
Specific Path:
Disallow: /private-section/
In this example, the entire “private-section” directory is off-limits to crawlers.
Wildcards:
* (Asterisk) – Represents any sequence of characters.
Disallow: /images/*.jpg
This disallows all JPEG images in the “images” directory.
$ (Dollar Sign) – Matches the end of the URL.
Disallow: /docs$
This disallows any URL ending with “/docs”.
? (Question Mark) – Represents a single character.
Disallow: /temp?file=*
This disallows URLs with a query parameter “file” in the “temp” directory.
Allow Values with Partial Paths
Allowing Specific Paths:
Allow: /public-section/
This allows crawlers to access the “public-section” directory.
Partial Path from Disallow Value:
Disallow: /private-section/
Allow: /private-section/public-subsection/
In this case, crawling is disallowed in the “private-section” directory but allowed in the “public-subsection” subdirectory.
Best Practices
- Be cautious with the use of wildcards, as they can have unintended consequences if not used carefully.
- Regularly update and review the Robots.txt file to ensure it aligns with the current structure and content of the website.
- Test the file using online tools to verify its effectiveness in controlling crawler access.
Conclusion
Robots.txt is a powerful tool for website owners to influence how search engines and other automated agents interact with their content. By understanding the various directives and values, site administrators can fine-tune the visibility of their pages in search engine results and maintain control over which parts of their site are accessible to web crawlers.
Tech Stack Thinker 