You can use the chmod command to grant or deny permission for directories as well as files. Simply specify a directory name instead of a file name on the command line.
However, consider the impact on various system users of changing permissions for directories. For example, suppose you grant read permission for a directory to yourself (u), members of your group (g), and other system users (o). Every user who has access to the system will be able to read the names of the files contained in that directory by running the ls -l command. Similarly, granting write permission allows the designated users to create new files in the directory and remove existing ones. Granting permission to execute the directory allows designated users to move to that directory (and make it their current directory) by using the cd command.