Change ownership of directory in ubuntu

For changing ownership of any folder or directory and its sub-directories in ubuntu 15.04/14.04 etc use this command.

sudo chown -R username:username /directory_name/

You need to enter your password.

Change permission of directory recursively in ubuntu

For changing permission of any folder or directory and its sub-directories in ubuntu 15.04/14.04 etc use following command.

sudo chmod -R 644 username:username /directory_name/