basherr

RewriteCond %{HTTPS} off
RewriteRule ^(.*)$ https://www.abc.com [L,R=301]
# .htaccess main domain to subdirectory redirect

# Do not change this line.

RewriteEngine on

RewriteCond %{HTTP_HOST} ^old.abc.com$   
RewriteRule !^oldwordpress/ oldwordpress%{REQUEST_URI} [L]