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Korn Shell 93

INTRODUCTION AND OVERVIEW

• Knowing when to use ksh
• Integrating KornShell scripts with external applications and tools
• Typical KornShell applications
• Differences between ksh88 and ksh93
• Benefits of KornShell vs. other shells

KORNSHELL FUNDAMENTALS

Shell script elements

• Commands and comments
• Defining exit values

Conditional program execution

• Applying if and case statements
• Simplifying if logic with elif

Program loops and iteration

• Conditional looping with while and until
• Pattern matching and list for loops

Testing files and strings

• Testing file age and permissions
• Comparing strings
• Verifying the existence of a string
• Testing with the [[ ]] command

Debugging

• Redirecting print as a debugging aid
• set commands for debugging

STORING AND ACCESSING DATA

Positional parameters

• Passing and accessing parameters
• Setting and unsetting parameters
• Manipulating parameters as groups

Shell variables

• Defining global and local variables
• Specifying default values and error conditions
• Writing reports by setting display characteristics

Arrays

• Creating and indexing arithmetic arrays
• Processing array contents with special variables

PROCESSING DATA

Manipulating strings

• Extracting substrings
• Determining string length

Mathematics under the KornShell

• Creating counting while loops
• Writing mathematical expressions: let vs. (( )), $(( ))

MODULAR PROGRAMMING WITH FUNCTIONS

KornShell function basics

• Functions vs. scripts
• Managing your variable namespace

Creating a function library

• Finding your library with FPATH
• Building a function library directory

INTERACTING WITH THE OUTSIDE WORLD

Manipulating files and redirecting data

• Processing command line parameters
• Deciphering redirection order
• Unraveling the secrets of exec: opening and closing multiple files

Interacting with running processes

• Handling error signals
• Defining post-termination actions such as notification, cleanup
• Reinitializing or getting status

Accessing network servers

• Contacting a network server
• Exchanging data with a network server

CREATING "PRODUCTION QUALITY" SCRIPTS

Ensuring environmental control

• Checking and modifying environment variables
• Using getopts to process command line options

Handling user interactions

• Setting up error processing
• Employing select to create a menu interface