Access Rights in Linux
| files | directories | |
|---|---|---|
| read (r) | Ability to access and view the contents of a file. | The ability to access and view the contents of a directory. |
| write (w) | The ability to save changes to a file. | The ability to save changes to a directory, i.e. such changes as creating, renaming or deleting the files enlisted in it. Requires the execute attribute to also be set. |
| execute (x) | The ability to execute a file insofar as it is a script, contains a program, or is a software binary. Or contains source code. | The ability to access a directory (i.e., “open” it), execute a file from within that directory, or perform a task that processes that directory (such as a search query). |
These are rights that can be set in Linux for files or directories, separately for three distinct identities or types of identity (Garn 2022, 62-63):
- User account owner of the file or directory, of which there can only be one
- Group ownership of the file or directory, of which there can only be one
- The non-owners of the file or directory, which is already inclusive of all other user accounts or groups
By default, the initial owners of new files or directories are the user account, and its primary group, responsible for that file’s creation (Garn 2022, 63).
Pgs. 64 / 74 - 72 / 82
Make sure to cover absolute and symbolic modes for arguments in permission changes using
chmod, permission string versus octal numeric formats, umask (change of default permissions for new files or directories), and file/directory attributes.
access_rights permission permissions Linux_permissions security digital_security Linux_security file-system type type_theory identity_type group user user_management user_account user_accounts users primary_group system_administration owners users account group Linux
bibliography
- Garn, Damon. The Official CompTIA Linux+ Student Guide (Exam XK0-005). 1.0. Downers Grove, IL: CompTIA, 2022.