Mastering BASH Scripts

This course deals comprehensively with the capabilities of BASH and the utilities commonly used in the development of scripts. The training concentrates on a common approach to BASH on variants of UNIX, and currently covers versions of BASH up to 4.1.

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This course is aimed at:

programmers and analysts operating in Unix environments using BASH, as well as Unix system and network managers. This course is particularly suitable for those companies, which take a multi-vendor open systems view, and is applicable to all flavours of UNIX including Linux, HP-UX, Solaris, AIX, and so on.

You will need:

  • Delegates should have a good working knowledge of Linux or UNIX systems, which includes a working knowledge of UNIX commands and utilities. This can be gained by attending our UNIX Fundamentals or Linux Essentials courses

  • Delegates should also have a practical understanding of programming concepts such as variables, and decision-making constructs.

You will learn to:

  • Use all significant features of the BASH language
  • Implement advanced variable and array manipulation
  • Develop shell scripts that contain advanced decision making constructs
  • Use the tracing features to speed the development of shell scripts
  • Implement advanced data stream handling by using process substitution
  • Incorporate functions in script design
  • Integrate BASH scripts with those written using other shells
  • Write reliable, maintainable and efficient shell scripts

Course Content:

Chapter 1: Introduction and Revision

  • Command-line structure
  • Shell interpretation
  • Filename expansion
  • Variable and command expansions
  • Quoting
  • Redirection
  • Here documents
  • Pipes

Chapter 2: Using BASH

  • The Bash story (in brief)
  • Bash personalities
  • Shell options
  • Bash shell options
  • Start-up files
  • Some shell variables
  • Aliases and functions
  • Command-line recall and editing
  • Navigation for the impatient
  • echo and help

Chapter 3: Shell Scripts

  • Command types
  • Creating shell scripts
  • Creating processes
  • The exec command
  • Exit status
  • Using # in shell scripts
  • Running shell scripts
  • BASH_ENV
  • Command groups and sub-shells

Chapter 4: Handling Variables

  • Legal variable names
  • Creating variables
  • The read command
  • Exporting variables
  • Special characters
  • Checking the environment
  • Eval

Chapter 5: Parameters and Friends

  • Positional parameters
  • Access to positional parameters
  • $*, $@, and $#
  • Changing positional aparmeters
  • $* versus $@
  • Other special variables

Chapter 6: Behaviour Therapy

  • Sending signals,
  • Receiving signals and the trap command
  • Shell tracing methods
  • Tracing shell expansions
  • DEBUG and ERR traps
  • Dry run of a script
  • The script command
  • Error messages are your friends

Chapter 7: Flow Control

  • Testing commands
  • 'if' statements
  • 'while' and 'until' loops
  • Bourne shell test command
  • Korn shell test command
  • Bourne and Korn syntax compared
  • Numeric tests

Chapter 8: Variable Expansion

  • Extracting a sub-string
  • Deleting a sub-string
  • Editing sub-strings
  • Test and set/exit expansions
  • The colon command

Chapter 9: Lofty Variables

  • Variable attributes
  • Compound assignments
  • Arithmetic conditionals
  • Working with floating-point

Chapter 10: More Loops

  • List processing - 'for' loop
  • Processing positional parameters
  • 'break' and 'continue'
  • Infinite loops
  • The 'select' loop
  • Reading in a loop from a file
  • Reading in a loop from a program (process substitution)

Chapter 11: Sophisticated Tests

  • Statement short-cuts
  • I/O redirection with if-then-fi
  • The 'case' statement
  • case flow control - Bash 4
  • Shell pattern matching
  • Extended pattern operators
  • Locales and character classes

Chapter 12: Using Functions

  • Functions vs. scripts
  • Creating functions
  • Listing and removing functions
  • Function parameters and return values
  • Local and global variables
  • Where to store functions
  • Exported functions
  • Using external function libraries

Chapter 13: Professional Scripts

  • Parsing script options with getopts
  • Handling errors
  • Formatting output - printf
  • Tips for shell programmers: programming for change
  • Tips for shell programmers: programming for performance

Chapter 14: Handling Arrays

  • Arrays: the concepts
  • Bash array syntax
  • Array syntax gotchas
  • Initialising arrays
  • Appending to an array
  • Finding array limits
  • Using read with an array
  • Using mapfile/readarray
  • Associative arrays

Chapter 15: Advanced IO

  • The concepts
  • Using file descriptors
  • Block redirection
  • Named pipes (FIFOs)
  • Process substitution

Chapter 16: Basic sed

  • Running sed
  • Basic regular expressions
  • sed line addressing

Chapter 17: Basic awk

  • The awk programming model
  • awk variables
  • awk opeators
  • Comparing awk with shell constructs

Certification:

This course will assist delegates preparing for the following exams:

  • LPI General Linux I - L101

£ 2,850.00 ex.vat

Data sheet

Course Duration 4 Days
Location London