If I place a regular expression in robots.txt will it be readable for the web crawlers?
2 Answers
No, the robots.txt syntax only supports wildcards, and not regular expressions. See here for a good discussion of the syntax: http://www.robotstxt.org/robotstxt.html.
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1
While it's not part of the standard robots.txt protocol (and therefore not globally recognized), Google and Bing both support LIMITED pattern matching.
For example:
User-agent: Googlebot
Disallow: /private*/
Will block Googlebot from any directory beginning with "private". Currently, Googlebot supports *
and $
(end of string).
Details on Googlebot's pattern matching: http://www.google.com/support/webmasters/bin/answer.py?hl=en&answer=156449
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Note that
Disallow: /private*/
does not block "any directory", but any URLs whose path begins with this string.– unorOct 19, 2013 at 20:45