The UNIX Korn Shell Language

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Libero
Version 2.32

The UNIX Korn Shell Language

Overview

What Is Korn Shell?: The Korn shell (/bin/ksh) is the most advanced 'standard' UNIX shell. It extends the Bourne shell with lots of nice features, and is a lot faster.
Portability: The Korn shell is standard when available, but is not supplied on all UNIX boxes.
Pros and Cons: Pros: supplied on most UNIXes; your scripts will run quickly. Cons: like all shells, slower than Awk or Perl or C.
How To Get It: Korn shell is available in a public-domain version (by Eric Baalberger) for Linux.

Working With The UNIX Korn Shell

Schema: lrschema.ksh.
Program model: executable UNIX script.
Good for: complex scripts; portable to GNU systems.
Files used/made: own work in myprog.mod; generates a script called myprog.
Module functions:
```
function module_function_name
{
```
Private functions: function private_function_name {
Naming style: any except -style=cobol.
Limits: 254 modules, 254 events, 1000 states. The schema checks at generate-time that the dialog does not exceed these limits. All tables are defined dynamically, at runtime.
Development cycle: run lr after you change the dialog or .mod file. When you add a new module, run lr, then edit the .mod file, then run lr again. Don't change the generated script except for hacking - you'll lose your changes.

Example of code

Code fragments:

#################   MODULE FUNCTION NAME   #################

function module_function_name
{
    return                      # Empty module needs 'return'
}

function private_function_name {
    the_next_event=$ok_event
    raise_exception $error_event
}

A fuller example.