I am new in using UbuntuServer13.10 so during giving permission to a folder to open it on FileZilla on other PC, I got these words and now I want to know about the difference between; "root", "user", "group", "guest" and their security levels. So can anyone explain to me briefly about their function and usage. Just the basics, or provide a link to an external article on them.
root: is a special account which is usually locked in Ubuntu. This account is in effect the ultimate super user and can change anything on the system. If you want to enable this account you can but its not recommended see How to enable root login? For how this can be done and a discussion on why its not recommended.
user: These are the users of your systems there are three types administrators, normal users and guest. Administrators can make major changes to the system while normal users can not. There is a useful summary in the RootSudo Comunity Documentation. The guest account is used to provide casual access to someone (to play a game, surf the web, etc.) without giving them access to other users files. Any files they create are automatically removed when they log out.
groups A user can be a member of one or more groups groups are used to control privileges within the system for example all administrators are in the
sudo group but you can also create you own groups. You may for example have a sales team who need to share some files but you want to prevent other people from accessing these files. By creating a special group for these people you can do that. See:How can I share a directory with an another user? for how you can set this up.
Ok here goes my best shot at explaining this.
First of all root is like what the System user name would be. It has the highest level of permissions available. Some apps require you to run them as root in order to unlock their full potential (i.e. to carry out tasks regularly unavailable to just an administrator/user) Secondly, user is kind of a generic term for your login or the login of another on the system (i.e. Joey, or Alice) Users are part of groups, There are different levels of groups such as Administrator, or User. Administrator is second to root, and User would follow Administrator. So inyour case file access permissions can be set to only allow one "User", or an entire "Group" of users. Some items are only accessable by root, which usally means that it is some system file or folder that you should consider avoiding messing with. To access these particular files and folders you can get there several different ways. Including by typing from the Terminal
This will start Nautilus with root permissions... Helps? -Bill