Question

What are the user access control permissions for file and directory defined in Unix/Linux? Draw a table showing permission type and symbol.

Hint:

Unix/Linux uses Read, Write, and Execute permissions for User, Group, and Others to control file and directory access.

Answer 1

Unix/Linux systems manage file and directory access through a permission system. This system applies three types of permissions to three categories of users:

• Permission Types:
  • Read (r): Grants the ability to view a file's content or list a directory's contents.
  • Write (w): Grants the ability to alter a file's content or add/remove files within a directory.
  • Execute (x): For files, allows running them as programs; for directories, allows entering or traversing them.
• User Categories:
  • User (u): Represents the owner of the file or directory.
  • Group (g): Encompasses other users who are members of the file's group.
  • Others (o): Includes all remaining users.

\begin{tabular}{|c|c|l|} \hline Permission & Symbol & Description
\hline Read & r & Ability to read file data or list directory contents
Write & w & Ability to modify file data or directory contents
Execute & x & Ability to run a file or access a directory
No Permission & - & Indicates the absence of a specific permission
\hline \end{tabular} These permissions are combined to define access rights for each user category. These rights are typically represented by a 9-character string, such as rwxr-xr--.