Diagnosing and correcting file permission problems (ls -l, namei -l, chmod, chown)

When a user gets Permission denied, the cause is almost always one of a few things: the wrong owner or group, missing permission bits on the file, or missing permission on a directory somewhere along the path. SELinux and ACLs (access control lists) can also block access, but start with standard permissions because they are checked first and are the most common exam problem.