rsh(1M) 						  System Administration Commands						   rsh(1M)

NAME

       rsh, restricted_shell - restricted shell command interpreter

SYNOPSIS

       /usr/lib/rsh [-acefhiknprstuvx] [argument...]

DESCRIPTION

       rsh  is a limiting version of the standard command interpreter sh, used to restrict logins to execution environments whose capabilities are
       more controlled than those of sh (see sh(1) for complete description and usage).

       When the shell is invoked, it scans the environment for the value of the environmental variable, SHELL. If it is found and rsh is the  file
       name part of its value, the shell becomes a restricted shell.

       The actions of rsh are identical to those of sh, except that the following are disallowed:

	 o  changing directory (see cd(1)),

	 o  setting the value of $PATH,

	 o  pecifying path or command names containing /,

	 o  redirecting output (> and >>).

       The restrictions above are enforced after .profile is interpreted.

       A restricted shell can be invoked in one of the following ways:

       1.  rsh is the file name part of the last entry in the /etc/passwd file (see passwd(4));

       2.  the environment variable SHELL exists and rsh is the file name part of its value; the environment variable SHELL needs to be set in the
	   .login file;

       3.  the shell is invoked and rsh is the file name part of argument 0;

       4.  the shell is invoke with the -r option.

       When a command to be executed is found to be a shell procedure, rsh invokes sh to execute it. Thus, it is possible to provide to  the  end-
       user  shell  procedures	 that  have access to the full power of the standard shell, while imposing a limited menu of commands; this scheme
       assumes that the end-user does not have write and execute permissions in the same directory.

       The net effect of these rules is that the writer of the .profile (see profile(4)) has complete control  over  user  actions  by	performing
       guaranteed setup actions and leaving the user in an appropriate directory (probably not the login directory).

       The  system administrator often sets up a directory of commands (that is, /usr/rbin) that can be safely invoked by a restricted shell. Some
       systems also provide a restricted editor, red.

EXIT STATUS

       Errors detected by the shell, such as syntax errors, cause the shell to return a non-zero exit status. If the  shell  is  being	used  non-
       interactively execution of the shell file is abandoned. Otherwise, the shell returns the exit status of the last command executed.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       intro(1), cd(1), login(1), rsh(1), sh(1),  exec(2), passwd(4), profile(4), attributes(5)

NOTES

       The restricted shell, /usr/lib/rsh, should not be confused with the remote shell, /usr/bin/rsh, which is documented in rsh(1).

SunOS 5.10							    1 Nov 1993								   rsh(1M)