Solaris

I have searched this quite a long time but couldn't find the right method for me to use. I need to assign read write permission to the user for specific directories and it's sub directories and files. I do not want to use ACL. This is for Solaris. Please help.

Hmm. chmod -R and chown -r are recursive and will work down from the directory on the command line on down. Also check out chgrp.

Anyway - with your restrictions you have some choices.

Some example choices:
For a single user you could create a unique group, just for the one person, and assign file permissions allowing that group access.

Create a sudo access privileged account and grant the user access that way ie., temporarily change the user, not the group.

Change ownership or group permissions of the file tree

Use RBAC and grant the user a role. Defining the role for the first time is not trivial, but is probably your best choice.

So, we need a lot more information -- FWIW why no ACL's? they would work easily.