I just created a new user on my Debian server, but I noticed that it hasn't all privileges to write in specific folders. So, I executed the command chown -R newuser:newuser / and it worked again.
But my question is: Is it secure to solve with this way? If not, how can I solve it? Thanks for the reply :)
Definitely not secure.
I suggest you learn how Access Control Lists work, apart from the special permissions. Mainly the getfacl & setfacl commands.
Nooo, if you ran that as root (or sudo) you just basically ruined the whole filesystem permission structure. You should probably reinstall or find a way to recreate the original set of permissions.
You might want to read more about the permissions in Unix. You have a separate set of permissions for the owner, a group, and everybody else. And then you have extended attributes.
Also, you can get new privileges for some time, using sudo.
