デフォルトの推奨CodeIgniter.htaccessファイル:
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#CodeIgniter
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /index.php/$1 [L]
RewriteRule ^$ /index.php [L]
</IfModule>
目的に合わせてCI.htaccessファイルを微調整しました(1年遅すぎます)。
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
#CodeIgniter
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
# Check for Domain 1 with a path
RewriteCond %{HTTP_HOST} domain-1.com
RewriteRule ^(.*)$ /site1-index.php/$1 [L]
# Check for Domain 1 without a path
RewriteCond %{HTTP_HOST} domain-1.com
RewriteRule ^$ /site1-index.php [L]
# Check for Domain 2 with a path
RewriteCond %{HTTP_HOST} domain-2.com
RewriteRule ^(.*)$ /site2-index.php/$1 [L]
# Check for Domain 2 without a path
RewriteCond %{HTTP_HOST} domain-2.com
RewriteRule ^$ /site2-index.php [L]
</IfModule>