k

ksh(1)

 

ksh(1)

whence

[ -pv] name ...

 

For each name, indicate how it would be interpreted if used as a command name. The -v

 

option produces a more verbose report. The -poption does a path search for name even if

 

name is an alias, a function, or a reserved word.

Invoking

ksh

 

If the shell is invoked by

exec (see exec(2)), and the ®rst character of argument zero ($0) is -, the shell is

assumed

to be a login

shell and commands are read ®rst from /etc/profile . The expression

${HOME:-.}/.profileis then evaluated and an attempt to open the resulting ®lename is made. If the ®le is opened successfully, the ®le is read. Next, commands are read from the ®le named by performing parameter substitution on the value of the environment parameter ENV, if the ®le exists. If the -soption is not present and arg is, a path search is performed on the ®rst arg to determine the name of the script to execute. When running ksh with arg, the script arg must have read permission and any setuid and getgid settings are ignored. Commands are then read as described below. The following options are interpreted by the shell when it is invoked:

-cstring

If the

-coption is present, commands are read from string.

-s

If the

-soption is present or if no arguments remain, commands are read from the

 

standard input. Shell output, except for the output of some of the Special Commands

 

listed above, is written to ®le descriptor 2.

-i

If the

-ioption is present or if the shell input and output are attached to a terminal,

 

the shell is interactive. In this case SIGTERM is ignored (so that kill 0 does not

 

kill an interactive shell) and SIGINT +1 is caught and ignored (so that wait is inter-

 

ruptible). In all cases, SIGQUIT is ignored by the shell. (See signal(5).)

-r

If the

-roption is present, the shell is a restricted shell.

The remaining options and arguments are described under the set command above.

rksh Only

rksh is used to set up login names and execution environments where capabilities are more controlled than those of the standard shell. The actions of rksh are identical to those of ksh, except that the following are forbidden:

∙Changing directory (see cd(1))

∙Setting the value of SHELL, ENV, or PATH

∙Specifying path or command names containing /

∙Redirecting output (>, >, <>, and >>)

The restrictions above are enforced after the .profile and ENV ®les are interpreted.

When a command to be executed is found to be a shell procedure, rksh invokes ksh to execute it. Thus, the end-user is provided with shell procedures accessible to the full power of the standard shell, while being restricted to a limited menu of commands. This scheme assumes that the end-user does not have write and execute permissions in the same directory.

When a shell procedure is invoked from rksh, the shell interpreter speci®ed with the #! magic inherits all the restricted features of rksh. So, the shell procedures written for execution under rksh with the intent of utilizing the full power of the standard shell should not specify an interpreter with #!.

These rules effectively give the writer of the .profile ®le complete control over user actions, by performing guaranteed set-up actions and leaving the user in an appropriate directory (probably not the login directory).

The system administrator often sets up a directory of commands (usually /usr/rbin) that can be safely invoked by rksh. HP-UXsystems provide a restricted editor red (see ed(1)), suitable for restricted users.

COMMAND-LINE EDITING

In-line Editing Options

Normally, each command line typed at a terminal device is followed by a new-line (carriage-return or line- feed). If either the emacs, gmacs, or vi option is set, the user can edit the command line. An editing option is automatically selected each time the VISUAL or EDITOR variable is assigned a value ending in either of these option names.

The editing features require that the user's terminal accept Return as carriage return without line feed and that a space character must overwrite the current character on the screen. ADM terminal users should set the ``space/advance'' switch to ``space''. Hewlett-Packard terminal users should set the straps to ``bcGHxZ etX''.

Section 1−412

− 17 −

HP-UX Release 11i: December 2000