alt Hacker Newsbash actually has a "restricted" mode which is sort of like that. In restricted mode, the following are disallowed:
- Changing directories with cd.
- Setting or unsetting the values of SHELL, PATH, HISTFILE, ENV, or BASH_ENV.
- Specifying command names containing /.
- Importing function definitions from the shell environment at startup.
- Parsing the values of BASHOPTS and SHELLOPTS from the shell environment at startup.
... some other things mainly preventing you from escaping or disabling the restricted mode.
Does that work? I've never seen it used. It seems easy to escape.
The docs seem to suggest using alternate approaches.
> Modern systems provide more secure ways to implement a restricted environment, such as jails, zones, or containers.
https://www.gnu.org/software/bash/manual/html_node/The-Restr...