How to check many sites for the presence of words?

Question

Google

Good afternoon. Can you please tell me how it is possible to check 16,000 sites for the presence of certain words on the main page? Automated. That is, for the robot to go to the main page of the site, check for the presence of the desired word, if found, then mark this site, then the next site, etc.
In general, the task is to find in the list of sites those sites that contain the desired word.

Answer 1

Write a robot, for example in php. Which will run through the database of your addresses, read and analyze their contents. How about here.

Answer 2

curl $HOMEPAGE$ | grep $KEYWORD
echo $?