Understanding file permissions in Linux

[Kristijntje]

Article covers file permissions, changing permissions with chmod, reading permissions with ls -l,  changing file and group ownership with chown and chgrp, setting SGID and SUID attributes, and more.

In GNU/Linux, file access is restricted. Users don't necessarily have the same rights when it comes to deleting, executing or even reading files. In fact, every file contain data such as its owner, its permissions and other information which defines exactly what can be done with it, and by whom.

Note: GNU/Linux treats everything as a file. As a consequence, directories use the same permission scheme.
Understanding file permissions

In GNU/Linux every user has his own user account, and is a member of one or more user groups. Similarly, each file belongs to a user and to a user group. For restricting file access, GNU/Linux (and Unix in general) defines three different types of rights:

- Read (symbolized by the letter r), which means that the file can be read;
- Write (symbolized by the letter w), which means that the content of the file can be changed;
- Execute (symbolized by the letter x), which means that the file can be executed.

full article: http://www.linuxforums.org/security/file...sions.html

[mandy]

A related article:

This article looks at user privileges and, in particular, examines how to manipulate file permissions to restrict or share your directories and files with others. Understanding permissions is crucial if you want to speak UNIX fluently.

full article: http://www-128.ibm.com/developerworks/ai...dgr-lnxw06