What is the importance of robot.txt in Seo?

Hello,
What is the importance of robot.txt in Seo?
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Robots.txt files are useful if you want search engines to ignore any duplicate pages or specific pages on your website.

thanks for comment...

Robots.txt file is a very simple but a very powerful tool in our hand to protect our web pages, particular directory of our website from getting indexed in search engines.
We can also block bots of a particular search engine through robots.txt file.

Robots.txt is a text file that lists webpages which contain instructions for search engines robots. The file lists webpages that are allowed and disallowed from search engine crawling.

Thank's Dear.

Robot.txt also known as robots exclusion protocol (REP) is a text file created to guide the search engine robots (web crawler) which information on the website should or should not be processed or scanned. In other word it is file to communicate with the web crawlers.

The robots.txt file, also known as the robots exclusion protocol or standard, is a text file that tells web robots (most often search engines) which pages on your site to crawl. It also tells web robots which pages not to crawl. Let's say a search engine is about to visit a site.

Thanks friends for your commenting.I get good knowledge. Again very very thanks.

Have you started SEO without knowing the importance of robots.txt?