I have a site in the name of www.mysite.com. when the url is www.mysite.com, I want to call index1.php file (this is my main domain).
If the url is from sub domains like test1.mysite.com, test2.mysite.com then I want to call index2.php file.
How to do it in htaccess?
If they are both in the same document root, put something like this in your htaccess file in the document root:
RewriteEngine On
RewriteCond %{HTTP_HOST} ^(www\.)?mysite\.com$ [NC]
RewriteRule ^$ /index1.php [L]
RewriteCond %{HTTP_HOST} !^(www\.)?mysite\.com$ [NC]
RewriteRule ^$ /index2.php [L]
If you have links to directory indexes that need to be rewritten, you can do those on a case-by-case basis, for example:
RewriteCond %{HTTP_HOST} ^(www\.)?mysite\.com$ [NC]
RewriteRule ^(.*)/index\.(php|html|htm)$ /$1/index1.php [L]
RewriteCond %{HTTP_HOST} !^(www\.)?mysite\.com$ [NC]
RewriteRule ^(.*)/index\.(php|html|htm)$ /$1/index2.php [L]
来源:https://stackoverflow.com/questions/12312906/how-to-call-different-index-files-for-main-domain-and-sub-domains