Restricted shells can be invoked in any of the following ways:
Restricted shells can also be set up by supplying the full pathname to rksh
in the shell field of /etc/passwd
or by using them as the value for the SHELL variable.
Restricted shells act the same as their nonrestricted counterparts, except that the following are prohibited:
Changing directory (i.e., using cd
Setting the PATH variable. rksh
also prohibits setting ENV and SHELL.
for command names or pathnames.
Redirecting output (i.e., using
also prohibits the use of
Adding new built-in commands (ksh93
Shell scripts can still be run, since in that case the restricted shell calls ksh
to run the script. This includes the /etc/profile
, and $ENV files.
Restricted shells are not used much in practice, as they are difficult to set up correctly.