Restricted shell

The restricted shell is a Unix shell that restricts some of the capabilities available to an interactive user session, or to a shell script, running within it. It is intended to provide an additional layer of security, but is insufficient to allow execution of entirely untrusted software. A restricted mode operation is found in the original Bourne shell and its later counterpart bash, and in the Korn shell. In some cases a restricted shell is used in conjunction with a chroot jail, in a further attempt to limit access to the system as a whole. The restricted shell is a Unix shell that restricts some of the capabilities available to an interactive user session, or to a shell script, running within it. It is intended to provide an additional layer of security, but is insufficient to allow execution of entirely untrusted software. A restricted mode operation is found in the original Bourne shell and its later counterpart bash, and in the Korn shell. In some cases a restricted shell is used in conjunction with a chroot jail, in a further attempt to limit access to the system as a whole. The restricted mode of the Bourne shell sh, and its POSIX workalikes, is used when the interpreter is invoked in one of the following ways: The restricted mode of bash is used when bash is invoked in one of the following ways: