GNU rush is a Restricted User Shell, designed for sites providing limited
remote access to their resources, e.g. scp, sftp, or access to VCS
repositories over ssh.  Accounts of the users that are allowed remote
access to the machine are configured to use /sbin/rush as the login
shell.

Using a flexible configuration file, GNU rush gives administrators
complete control over the commands that users are allowed to run and their
possible arguments.  It also makes it possible to run commands in chrooted
environments, limit usage of system resources, and do various other
administrative tasks.