The hosts file isn't really made to be edited with a script, but I suppose it's possible to do. I would just be careful and test your process thoroughly before deploying it out to a lot of machines.
The command I would probably use for this is sed. But you have to direct sed to make changes directly to the file, because normally it takes a stream input and sends the changes to output, not back to a file. Directing sed to make edits directly to a file looks something like this:
/usr/bin/sed -i "" '/url_or_string_here/d' /etc/hosts
Replace the url_or_string_here with something that should be unique in the hosts file to locate the line to be deleted. If the string has any slashes in it, you'll need to either escape them or use some other divider with sed, since it uses / as the delimiter for what to look for and what action(s) to take by default.
As I said, I would be careful with this so as not to mess up the hosts file. Test it out a bunch on some machines that you can easily fix if something goes wrong.
