To change all directories to 755 i.e. when you are using suphp and you have your directories are having the wrong permission:
find /home/userid/public_html/directorywheretochangein -type d -print0 | xargs -0 chmod 755
to change the permissions for the files change the type from d to f ; and obviously change the chmod to i.e. 644 which is needed for suphp.
