All operations described below require that you know the root password and can su in as root. Setting file permissions in Linux is an integral part of administrating any Linux machine. It is especially useful in servers which allow remote access to your Linux machine, such as FTP servers, SSH remote access machines, Samba file servers, and so on. By setting the file permissions for each folder, the system administrator can control who can read, execute, or write to any file on your system. However, changing permissions on system files incorrectly in Linux can have a dire effect on the stability and usability of your Linux install. It is recommended that you start slowly when exploring how to change file permissions. Overview of File Permissions Changing File Permissions Applications of File Permissions