May 2010
Beginner to intermediate
130 pages
3h 20m
English
A restricted shell is one that
disallows certain actions, such as changing directory, setting
PATH, or running commands whose names contain a
/ character.
The original V7 Bourne shell had an undocumented restricted mode. Later versions of the Bourne shell clarified the code and documented the facility. Bash also supplies a restricted mode. (See the manual page for the details.)
Shell scripts can still be run, since in that case the restricted shell calls the unrestricted version of the shell to run the script. This includes /etc/profile, $HOME/.profile, and the other startup files.
Restricted shells are not used much in practice, as they are difficult to set up correctly.