Redirect all posts urls from without .html to .html

How can i redirect all posts permalinks to .html ,in WordPress ? now all my posts url are ending in .html ,but before it was without .html

to be more clear ,for example a post url like this www.example.com/posturl to be redirected to www.example.com/posturl.html .it’s simple to redirect them one by one,but i need a rule to redirect all posts .

Thank you

You can edit your .htaccess directly or download an htaccess editor plugin for WordPress. Then write your rule similar to this:

Options +FollowSymlinks
RewriteEngine on
RewriteRule ^(.*) $1.html [nc]

For more detailed instructions