<IfModule mod_rewrite.c>
 
    RewriteEngine On
    RewriteBase /
 
    ### Canonicalize codeigniter URLs
 
    # If your default controller is something other than
    # "welcome" you should probably change this
    RewriteRule ^(welcome(/index)?|index(\.php)?)/?$ / [L,R=301]
    RewriteRule ^(.*)/index/?$ $1 [L,R=301]
 
    # Removes trailing slashes (prevents SEO duplicate content issues)
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.+)/$ $1 [L,R=301]
 
    # Enforce www
    # If you have subdomains, you can add them to 
    # the list using the "|" (OR) regex operator
    RewriteCond %{HTTP_HOST} !^(www|subdomain) [NC]
    RewriteRule ^(.*)$ http://www.domain.tld/$1 [L,R=301]
 
    # Enforce NO www
    #RewriteCond %{HTTP_HOST} ^www [NC]
    #RewriteRule ^(.*)$ http://domain.tld/$1 [L,R=301]
 
    ###
 
    # Removes access to the system folder by users.
    # Additionally this will allow you to create a System.php controller,
    # previously this would not have been possible.
    # 'system' can be replaced if you have renamed your system folder.
    RewriteCond %{REQUEST_URI} ^system.*
    RewriteRule ^(.*)$ /index.php/$1 [L]
 
    # Checks to see if the user is attempting to access a valid file,
    # such as an image or css document, if this isn't true it sends the
    # request to index.php
    RewriteCond %{REQUEST_FILENAME} !-f
    RewriteCond %{REQUEST_FILENAME} !-d
    RewriteRule ^(.*)$ index.php/$1 [L]
 
</IfModule>
 
<IfModule !mod_rewrite.c>
 
    # Without mod_rewrite, route 404's to the front controller
    ErrorDocument 404 /index.php
 
</IfModule>

이렇게 했구요