Now,I am going to tell you How To make and add custom robot.txt for your blogger site .At first go to the this (http://ctrlq.org/blogger/ ) site to create / enable XML Google map site.
After entering that site you will get a page which provide you to create sitemap as like as below.
Give your blog url on this gap box,then click on Generate Sitemap.
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After clicking you will get some html code like below.
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Copy all this code,
Then,Login to your blogger account Then click Setting-> Search preference ->Custom robot.txt.
Then paste the code you has been copied,to the custom robot.txt blank page like below.
Then click save.That's all done.
After entering that site you will get a page which provide you to create sitemap as like as below.
Give your blog url on this gap box,then click on Generate Sitemap.
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After clicking you will get some html code like below.
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Copy all this code,
Then,Login to your blogger account Then click Setting-> Search preference ->Custom robot.txt.
Then paste the code you has been copied,to the custom robot.txt blank page like below.
Then click save.That's all done.
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