ksh

ksh Command



Purpose

Invokes the Korn shell.

Syntax

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

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

Description

The ksh command invokes the Korn shell, which is an interactive command
interpreter and a command programming language. The shell carries
out commands either interactively from a terminal keyboard or from
a file.

The Korn shell is backwardly compatible with the Bourne shell (invoked
with the bsh command) and contains most of the Bourne shell features
as well as several of the best features of the C shell.

Flags

-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 ksh command line.

-r	Runs a restricted shell. With a restricted shell you 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).

-s	Causes the ksh 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

/usr/bin/ksh	Contains the path name to the Korn shell.

/tmp/sh*	Contains temporary files that are created when a shell is
opened.

Related Information

The profile file format.

Korn Shell in AIX Version 4 System User's Guide: Operating System
and Devices.