BASH Programming Training Course

The simplest script

Choosing the shell (magic number #!, Sha-bang)

Executing the script

External and built-in commands

Key special characters

• Comments (#)
• End of line (;)
• Empty statement (:)
• Input/output redirection (>, <, >>)
• Output redirection
• Input redirection
• Streams (|)
• Running processes in the background (&)

Variables and Parameters

• Removing variables (unset)
• Variables with null values
• Storing results in variables (backquotes ``)
• Parameter references ($ 0, $ #, $ 1, $ 2, $ 3 ...)
• Manual shifting of parameters
• Quoting strategies
• Escape characters (\)

Regular Expressions

Conditional statements

• The if / then construct
• The if / then / else construct
• Nesting if statements
• The if / elif construct
• Case statements
• Logical operators
• AND, OR operators (&&, ||)
• The test command

Completing scripts

The exit statement

Utilizing the script's exit status ($?)

Tests and Operators

• File operator tests
• File type tests
• File attribute tests

Comparison operators

• Arithmetic comparisons using the if command
• Integer comparison operators
• String comparisons
• Complex comparisons (AND, OR)
• Nesting comparison operators
• Assignment operators
• Arithmetic operators
• Bitwise operators
• Logical operators
• Numeric constants

Loops

• The for / in loop
• The seq command
• The while loop
• The until loop
• Loop control (break, continue)

Text Processing

• head and tail commands
• sort, uniq, expand, unexpand commands
• cut, paste, join, wc, tr commands

Text searching (grep)

Stream editor (sed)

Interactive programs

• read command
• select command

Features

sleep command

Troubleshooting (debugging)