Forum Moderators: phranque
Is it your intention to just "fix" mis-types, or do you want to use (and link to) extensionless page URLs on your site?
Your answer determines many aspects of the solution, starting with whether the correct solution is an external redirect or an internal rewrite, and how many steps are involved.
Jim
# If requested URL plus .shtml resolves to an existing file
RewriteCond %{REQUEST_FILENAME}.shtml -f
If that pattern matches and the RewriteCond is true, you'd then 301-redirect to the domain, plus the back-reference, plus ".shtml"
If you have any trouble, post your code for further discussion.
Jim