I am running Ubuntu on a Oracle Vbox in Windows 7 to develop a website. I have a set of directories that have Owner rw permissions but the group www-data does not have rights on the directories . I tried the command
sudo chmod 640 /path-to-directory to change the status, but receive a message requesting my www-data password. My owner level password does not work and I do not know what this password might be. I tried
passwd and receive the message 'changing the password for www-data and a prompt for my current unix password. When I enter it I get the error message
passwd: Authentication token manipulation error
passwd: password unchanged
This error message looks more like some sort of problem on my system, but everything else works fine.