You can do it with WP-CLI. wp post create will create a post.
wp post create ./file.txt --post_status=Publish
where file.txt contains the content you want to add (in HTML format).
To post it multiple time use a for loop.
You can use wp post update if you want to update existing post.
First step check your post ID using
wp post list
Now update the post
wp post update <ID_1> --status=Publish --from-post=<ID_2>
Where ID_1 is the ID of the page you want to copy TO and ID_2 is the id of the page you want to duplicate from.