Linux Bash Shell Programming

Course Introduction

• Administration and Course Materials
• Course Structure and Agenda
• Delegate and Trainer Introductions

Session 1: UNIX COMMAND REVIEW

• Basic Unix commands
• General commands
• File and directory handling commands
• Filename generation characters
• I/O Redirection features
• Other commands

Session 2: GETTING STARTED

• What is a shell script?
• Development guidelines
• Creating and editing shell scripts
• Naming and storing shell scripts
• Executing shell scripts
• Exercise: Write a simple shell script

Session 3: USING VARIABLES

• Environment variables
• Local variables
• Assigning values to variables
• Assessing variable values
• Using quotes
• Delimiting variable names
• Echo control sequences
• Exercise: Add variables to a script

Session 4: INTEGER ARITHMETIC

• Using the expr command
• Using the (( )) notation
• Exercises: Add integer arithmetic to a shell script

Session 5: HANDLING RUN TIME DATA

• The read command
• Command line arguments
• Exercise: Writing a generic shell script
• Exercise: Writing an interactive shell script

Session 6: CONDITIONAL EXECUTION

• The if statement
• The test command
• Exercise: Adding validation to previous scripts

Session 7: ADDITIONAL KORN, BASH & POSIX SYNTAX

• Other test notations
• Default and substitute variables
• Exit status codes
• Exercise

Session 8: LOOP CONSTRUCTS

• The while loop
• The until loop
• The for loop
• The while true and until false loops
• Loop control commands
• Exercise: Enhancing the previously written scripts
• Exercise: Writing a script to copy files using a 'for' loop
• Exercise: Writing a script to generate numbers with the 'while' loop

Session 9: MULTI-BRANCH DECISIONS

• The case statement
• Menu driven applications
• Exercise: Developing and writing a menu system

Session 10: FUNCTIONS

• What is a function?
• Syntax
• Examples
• Creating a Function Library
• Exercise: Add a function to a script

Session 11: INTERRUPT HANDLING

• Interrupt signals
• Trapping interrupts
• Exercise: Adding traps to the menu script

Session 12: ADDITIONAL FEATURES AND FACILITIES

• The exec commands
• The includes notation
• More about loops
• Arrays
• Here Documents
• Exercise: Create a here script

Session 13: BACKUP AND RESTORE UTILITIES

• Backing-up and restoring files
• Basic and advanced use of tar
• Compression utilities gzip, bzip2, zip and compress
• Exercise: Backing up and restoring files using tar
• Exercises: Compressing files

Session 14: BACKGROUND JOB SCHEDULING

• Scheduling jobs with the cron command
• Scheduling jobs with the at command
• Exercises: Running background jobs

Session 15: COMMANDS FOR COMPARING FILES

• Compare two files with the cmp command
• Compare two files with the comm command
• Compare two files with the diff and sdiff commands
• Compare large files with the bdiff command
• Exercises: Identifying file differences

Session 16: SPLITTING FILES

• The split and csplit commands
• Exercises: Splitting files

Session 17: IDENTIFYING AND TRANSLATING CHARACTERS

• od - octal dump
• Use cat to display non-printing characters
• The expand and unexpand commands to convert between tab and space characters
• The tr command for character translation
• Exercises: Translating characters with tr

Session 18: REGULAR EXPRESSION NOTATION REVIEW

• Standard regular expressions
• Extended regular expressions

Session 19: THE STREAM EDITOR sed

• sed command line syntax
• sed script files
• sed command processing
• sed addresses and simple instructions
• sed pattern space and hold space
• Grouping sed commands
• Hold and get functions
• Advanced flow control
• Exercises: Text processing with sed

Session 20: FUNDAMENTALS OF AWK

• Basic AWK usage
• AWK program-files
• AWK scripts
• AWK variables
• Pattern matching with AWK
• AWK extended patterns
• AWK operators
• AWK arithmetic operations
• AWK output
• Formatting output with printf
• Exercises: Create awk scripts to extract selected data from a file and generate reports

Session 21: AWK PROGRAM CONTROL STRUCTURES

• The BEGIN and END functions
• The AWK if construct
• The AWK else if construct
• The AWK while construct
• Other program control statements
• The AWK break, continue and exit statements
• User defined functions
• Exercises: Create AWK scripts and program-files utilising program control structures

Session 22: AWK FUNCTIONS

• AWK string functions
• AWK length, tolower, toupper, index, sub, gsub, match, substr, split, sprintf, system and getline functions
• Exercises: Generate AWK scripts and program-files to extract and format data using AWK functions

Session 23: AWK ARRAYS

• AWK associative arrays
• Multi-dimensional arrays
• Exercises: Create AWK associative arrays to process text files and generate reports

Session 24: MISCELLANEOUS TOOLS

• bc (calculator)
• fuser (testing for files in use)
• getops (checking options passed to shell scripts)
• printf (formatting screen output)
• logger (script logging)
• xargs (generating arguments for a command)
• eval (re-evaluating variables)
• Exercises: Using tools within a shell script