Computer Science 2211A/B Study Guide - Quiz Guide: Chmod, Umask
17 Dec 2022
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Document Summary
F i le secur ity and perm iss ions. File security unix is a multi-user operating system. Every file has 3 categories of users with permissions. A user can be a member of any number of groups. A group can contain any number of users. Every has a group identical to their username. Each category of users have 6 permissions applied to it: Read - ability to read the contents of a file/directory. Write - ability to create/update/remove the a file/directory. Execute - ability to execute the file or "search" the directory. Symlinks take on the permissions of what they are linked to. Permissions either granted (a letter) or not (a dash) r / - w / - x / - There are 512 possible combinations for each file: --------- a regular file with no permissions granted. Rwxrwxrwx a regular file with all permissions granted. Rwx------ a regular file with all permissions for owner only.
