rsh(C)                          19 June 1992                          rsh(C)


 Name

    rsh - invoke a restricted shell (command interpreter)

 Syntax

    rsh [ flags ] [ name [ arg1 ... ] ]

 Description

    rsh is a restricted version of the standard command interpreter sh(C).
    It is used to set up login names and execution environments whose capa-
    bilities are more controlled than those of the standard shell.  The
    actions of rsh are identical to those of sh, except that changing direc-
    tory with cd, setting the value of $PATH, using command names containing
    slashes, and redirecting output using > and >> are all disallowed.

    When invoked with the name -rsh, rsh reads the user's .profile (from
    $HOME/.profile).  It acts as the standard sh while doing this, except
    that an interrupt causes an immediate exit, instead of causing a return
    to command level.  The restrictions above are enforced after .profile is
    interpreted.

    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 shell pro-
    cedures to the end user that have access to the full power of the stan-
    dard shell, while restricting the user to 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 has com-
    plete control over user actions, by performing guaranteed setup actions,
    then leaving the user in an appropriate directory (probably not the login
    directory).

    rsh is actually just a link to sh and any flags arguments are the same as
    for sh(C).

    The system administrator often sets up a directory of commands that can
    be safely invoked by rsh.

 See also

    sh(C), profile(M)