rbash

rbash is a restricted bash shell, designed to provide limited functionality for users on Unix-like operating systems. It is primarily used as a secure restricted shell for users who require restricted access to the system.

With rbash, administrators can impose restrictions on a user's capabilities, preventing them from executing certain commands and accessing specific files and directories.

rbash limits users to their home directory and prevents them from changing directories to locations outside their designated directory.

Users in rbash are also restricted from running commands with specific paths or names, specified by the administrator.

Additionally, rbash disables certain features of the bash shell, such as the ability to modify environment variables, change the current working directory, and redirect input/output streams.

The restricted shell also prevents users from executing external commands, such as those found in the user's PATH, by excluding the current directory from the search path.

rbash can be useful for providing restricted remote access to systems or when a user requires limited privileges while still needing some functionality of the interactive shell.

Users in rbash can still use basic read-only commands like ls, cd, and echo, allowing them to view their files and navigate within their restricted environment.

However, they won't be able to use advanced shell features like tab completion, command history, or shell scripting capabilities.

Overall, rbash reinforces system security by limiting the actions and access available to users in a Unix-like environment.