Suddenly the following problem has happened:
I have an Apache web directory at /www. Everything was ok with the permissions, but at some point (I can't realize what caused it), I become unable to create any new files in this directory.
I have tried two methods:
Saving a new file from Sublime
sudo echo "" > newfile.
But both methods failed. On the other hand I am able to create new files in my home directory (using both mentioned ways) and then to copy or move them to /www. What may be the issue and how to solve it?