rksh Command

Purpose

Invokes the restricted version of the Korn shell.

Syntax

rksh [ -i ] [ { + | - } { a e f h k m n p t u v x } ] [ -o Option ... ] [ -c String | -s | File [ Parameter ] ]

Note: Preceding a flag with + (plus) rather than - (minus) turns off the flag.

Description

The rksh command invokes a restricted version of the Korn shell. It allows administrators to provide a controlled shell environment to the users. There is also a restricted version of rksh available for the enhanced Korn shell, called rksh93.

With a restricted shell a user cannot:

Change the current working directory.
Set the value of the SHELL, ENV, or PATH variable.
Specify the pathname of a command that contains a / (slash).
Redirect output of a command with > (right caret), >| (right caret, pipe symbol), <> (left caret, right caret), or >> (two right carets).

For more information about the restricted Korn shell, refer to Restricted Korn shell in AIX® Version 7.1 Operating system and device management.

Flags

Item	Description
-a	Exports automatically all subsequent parameters that are defined.
-c String	Causes the Korn shell to read commands from the String variable. This flag cannot be used with the -s flag or with the File[Parameter] parameter.
-e	Executes the ERR trap, if set, and exits if a command has a nonzero exit status. This mode is disabled while reading profiles.
-f	Disables file name substitution.
-h	Designates each command as a tracked alias when first encountered.
-i	Indicates that the shell is interactive. An interactive shell is also indicated if shell input and output are attached to a terminal (as determined by the ioctl subroutine). In this case, the TERM environment variable is ignored (so that the kill 0 command does not kill an interactive shell) and the INTR signal is caught and ignored (so that a wait state can be interrupted). In all cases, the QUIT signal is ignored by the shell.
-k	Places all parameter assignment arguments in the environment for a command, not just those arguments that precede the command name.
-m	Runs background jobs in a separate process and prints a line upon completion. The exit status of background jobs is reported in a completion message. On systems with job control, this flag is turned on automatically for interactive shells.
-n	Reads commands and checks them for syntax errors, but does not execute them. This flag is ignored for interactive shells.
-o Option	Prints the current option settings and an error message if you do not specify an argument. You can use this flag to enable any of the following options: allexport Same as the -a flag. errexit Same as the -e flag. bgnice Runs all background jobs at a lower priority. This is the default mode. emacs Enters an emacs-style inline editor for command entry. gmacs Enters a gmacs-style inline editor for command entry. ignoreeof Does not exit the shell when it encounters an end-of-file character. You must use the exit command, or override the flag and exit the shell by pressing the Ctrl-D key sequence more than 11 times. keyword Same as the -k flag. markdirs Appends a / (slash) to all directory names that are a result of filename substitution. monitor Same as the -m flag. noclobber Prevents redirection from truncating existing files. When you specify this option, use the redirection symbol >\| (right caret, pipe symbol) to truncate a file. noexec Same as the -n flag. noglob Same as the -f flag. nolog Prevents function definitions from being saved in the history file. nounset Same as the -u flag. privileged Same as the -p flag. verbose Same as the -v flag. trackall Same as the -h flag. vi Enters the insert mode of a vi-style inline editor for command entry. Entering escape character 033 puts the editor into the move mode. A return sends the line. viraw Processes each character as it is typed in vi mode. xtrace Same as the -x flag. You can set more than one option on a single rksh command line.
-p	Disables the processing of the $HOME/.profile file when you use the shell as a login shell.
-s	Causes the rksh command to read commands from the standard input. Shell output, except for the output of the special commands, is written to file descriptor 2. This parameter cannot be used with the -c flag or with the File[Parameter] parameter.
-t	Exits after reading and executing one command.
-u	Treats unset parameters as errors when substituting.
-v	Prints shell input lines as they are read.
-x	Prints executed commands and their arguments.

Files

Item	Description
/usr/bin/rksh	Contains the path name to the restricted Korn shell.
/tmp/sh*	Contains temporary files that are created when a shell is opened.