What is the primary purpose of the 'su' command in Linux?

• A. Temporarily switch to a different user
• B. Display user permissions
• C. Log out the current user
• D. Shut down the system

Answer: (A)

The primary purpose of the 'su' command in Linux is to temporarily switch to a different user. When you use 'su' followed by a username, you can assume that user’s identity and permissions for the duration of the session, provided you have the necessary credentials (such as the target user's password). This functionality is particularly useful for gaining elevated privileges to perform administrative tasks or access files and commands that are restricted to specific users.

While displaying user permissions, logging out the current user, and shutting down the system are also important operations in Linux, they are not the main function of the 'su' command. Instead, those tasks are typically handled by other commands such as 'id' for user permissions, 'logout' or 'exit' for logging out, and 'shutdown' or 'poweroff' for shutting down the system.