Can someone assist me to modify this code. i don't know how you can modify htaccess.

<IfModule mod_rewrite.c>
    RewriteEngine on

    RewriteRule (some_folder/.*) $1 [L] # adjust the regex to what you want.

    # normal cake rules
    RewriteRule ^$ webroot/ [L]
    RewriteRule (.*) webroot/$1 [L]
 </IfModule>

i wanna redirect all address blog/* to blog/

You most likely want:

RewriteRule ^blog/?(.*)$ blog/ [L]

I am unsure why you would ignore area of the URL though. Would you like to pressure the address to blog/ rather than a transparent redirect? Use [R] rather than [L]

To override CakePHP redirects, you could attempt placing:

RewriteRule ^/blog(/?.*)$ /blog$1 [L]

before

RewriteRule (.*) webroot/$1 [L]