Keeping your files private from anyone but those with superuser (root) access is easy on Linux. File permissions provide everything you need. By default, you’ll have a username and primary group assigned to your account, and you can use the chmod (change mode) command to control what anyone else can view or change.
(If permissions like “750” and “rwxr-x—” don’t ring any bells for you, check out these posts for insights into how file permissions work on Linux: A deeper dive into Linux permissions and Unix: beyond group and everyone else)
Source:: Network World – Data Center