To begin, we're going to go right back to basics by taking a look at the default Linux file permissions.
In this section, we're going to use a file and a directory on our CentOS box, to highlight some important and basic knowledge that we can use going forward.
File permissions on Unix and Unix-like systems are different from those found on Windows and other OS installations. If you connect a hard drive formatted with a Unix file-system (such as XFS) to a Windows box, it is unlikely it will be able to read the permissions on the files accurately (unless you've got software to do it for you). These lines have been blurred a bit in recent years, thanks to things like the Windows Subsystem for Linux included in Windows 10, but the principle is basically true.