I recently started messing with some files on a virtual hosted machine and I was logged in a normal/non-root user. At first everything was fine, I was able to install anything I needed using:
sudo apt-get install tree
But I somehow messed up a file where now when I do that I get the following error:
sudo: can't open /etc/sudoers: Permission denied
I'm not sure how to diagnose this, I've googled for solutions but everything's about what sudo is and nothing related to what to do about re-enabling users to use it.
Let me know if you'd like any other details in comments :)
ls -l /etc/sudoers -r--r----- 1 root root 577 Apr 20 03:42 /etc/sudoers