PWB1/usr/man/man1/rsh.1

.th RSH I 5/31/77
.sh NAME
rsh  \*-  restricted shell (command interpreter)
.sh SYNOPSIS
.bd rsh
[
.bd \*-x
] [
.bd \*-
] [
.bd \*-ct
]
[ name [ arg1 ... ] ]
.sh DESCRIPTION
.it Rsh
is a restricted version of the standard command interpreter
.it "sh(I)."
It is used to set up login names or execution environments whose
capabilities are more controlled than that of the standard shell.
The actions of
.it rsh
are identical to those of
.it sh,
except for the following restrictions:
.s3
.lp +5 5
1)	\c
.it chdir
is not allowed.
.s3
.lp +5 5
2)	changes to the shell variable `$p' are not permitted.
.s3
.lp +5 5
3)	it is illegal to use `/' in the name of a command.
.s3
.lp +5 5
4)	\c
.it next
is not permitted.
.s3
.lp +5 5
5)	`>' and `>>' are disallowed.
.s3
.i0
These restrictions combine to lock a user into the login directory,
limit the set of invokable commands to those found in
directories included in the `.path' file,
and eliminate the direct creation or
modification of files.
When a command to be executed is found to be a shell procedure,
.it rsh
invokes
.it sh
to execute it.
Thus, it is possible to write shell procedures using the full power of
the standard shell,
while the end user is restricted to a limited menu of commands.
.s3
.it Rsh
is actually just a link to
.it sh.
.sh FILES
/etc/glob,
which interprets `*', `?', and `['.
.br
/dev/null as a source of end-of-file.
.br
\&.path in login directory to initialize $p.
.br
\&.profile in login directory for general initialization.
.br
/etc/sha for accounting information.
.sh "SEE ALSO"
sh(I)
.sh BUGS
It would be better to have a flag for
.it opt
which changed
.it sh
into
.it rsh
dynamically.
With a non-interruptable `.profile',
it would be possible to act as
.it sh,
use
.it chdir
(for example), and then change into
.it rsh
at the end of initialization.