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Introduction

This tutorial is a beginners handbook for new Linux users / Sys admins and school students studying Linux or computer science. This book is licensed under"Creative Commons Attribution Noncommercial Share Alike 3.0 Unported".

 Linux Shell Scripting Tutorial (LSST) v2.0

Written by Vivek Gite. Copyright 1999-2010 Vivek Gite and its contributors. Some rights reserved.

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Chapter 1: Quick Introduction to Linux

• What Is Linux?
• Who created Linux?
• Where can I download Linux?
• How do I Install Linux?
• Linux usage in everyday life
• What is Linux Kernel?
• What is Linux Shell?
• Unix philosophy
• But how do you use the shell?
• What is a Shell Script or shell scripting?
• Why shell scripting?
• Chapter 1 Challenges

Chapter 2: Getting Started With Shell Programming

• The bash shell
• Shell commands
• The role of shells in the Linux environment
• Other standard shells
• Write a simple shell script - "Hello World!"
  • Starting a script with Shebang line (#!)
  • Comments in a script
  • Setting up permissions on a script
  • Execute a script
  • Debug a script
• Chapter 2 Challenges

Chapter 3:The Shell Variables and Environment

• Variables in shell
  • Assign values to shell variables
  • Default shell variables value
  • Rules for Naming variable name
  • Display the value of shell variables
  • Quoting
  • The export statement
  • Unset shell and environment variables
  • Getting User Input Via Keyboard
• Perform arithmetic operations
  • Create an integer variable
  • Create the constants variable
• Bash variable existence check
• Customize the bash shell environments
  • Recalling command history
  • Path name expansion
  • Create and use aliases
  • The tilde expansion
  • Startup scripts
    • Using aliases
    • Changing bash prompt
    • Setting shell options
    • Setting system wide shell options
• Chapter 3 Challenges

Chapter 4: Conditionals Execution (Decision Making)

• Bash structured language constructs
• Test command
• if structures to execute code based on a condition
• If..else..fi
• Nested ifs
• Multilevel if-then-else
• The exit status of a command
• Conditional execution
• Logical AND &&
• Logical OR ||
• Logical Not !
• Conditional expression using [ (portable version)
• Conditional expression using [[
• Numeric comparison
• String comparison
• File attributes comparisons
• Shell command line parameters
  • How to use positional parameters
  • Parameters Set by the Shell
  • Create usage messages
  • Exit command
• The case statement
  • Dealing with case sensitive pattern
• Chapter 4 Challenges

Chapter 5: Bash Loops

• The for loop statement
• Nested for loop statement
• The while loop statement
  • Use of : to set infinite while loop
• The until loop statement
• The select loop statement
  • Exit the select loop statement
• Using the break statement
• Using the continue statement
• Command substitution
• Chapter 5 Challenges

Chapter 6: Shell Redirection

• Input and Output
• Standard input
• Standard output
• Standard error
• Empty file creation
• /dev/null discards unwanted output
• here documents
• here strings
• Redirection of standard error
• Redirection of standard output
• Appending redirected output
• Redirection of both standard error and output
• Writing output to files
• Assigns the file descriptor (fd) to file for output
• Assigns the file descriptor (fd) to file for input
• Closes the file descriptor (fd)
• Opening the file descriptors for reading and writing
• Reads from the file descriptor (fd)
• Executes commands and send output to the file descriptor (fd)
• Chapter 6 Challenges

Chapter 7: Pipes and Filters

• Linking Commands
• Multiple commands
• Putting jobs in background
• Pipes
  • How to use pipes to connect programs
  • Input redirection in pipes
  • Output redirection in pipes
  • Why use pipes
• Filters
• Chapter 7 Challenges

Chapter 8: Traps

• Signals
  • What is a Process?
  • How to view Processes
  • Sending signal to Processes
  • Terminating Processes
  • Shell signal values
• The trap statement
• How to clear trap
• Include trap statements in a script
• Use the trap statement to catch signals and handle errors
• What is a Subshell?
  • Compound command
  • exec command
• Chapter 8 Challenges

Chapter 9: Functions

• Writing your first shell function
  • Displaying functions
  • Removing functions
• Defining functions
• Writing functions
• Calling functions
• Pass arguments into a function
  • local variable
• Returning from a function
• Shell functions library
  • Source command
• Recursive function
• Putting functions in background
• Chapter 9 Challenges

Chapter 10: Interactive Scripts

• Menu driven scripts
  • Getting information about your system
• Bash display dialog boxes
  • dialog customization with configuration file
  • A yes/no dialog box
  • An input dialog box
  • A password box
  • A menu box
  • A progress bar (gauge box)
  • The file selection box
  • The form dialog for input
• Console management
  • Get the name of the current terminal
  • Fixing the display with reset
  • Get screen width and hight with tput
  • Moving the cursor with tput
  • Display centered text in the screen in reverse video
  • Set the keyboard leds
    • Turn on or off NumLock leds
    • Turn on or off CapsLock leds
    • Turn on or off ScrollLock leds
• Display KDE / GTK+ GUI dialog
  • zenity: Shell Scripting with Gnome
  • kdialog: Shell scripting with KDE
• notify-send: Send desktop notifications
• Chapter 10 Challenges

To do

• Work in progress