BASH Programming Training Course

The Simplest Script

Selecting the Shell (Shebang #!)

Invoking the Script

External and Built-in Commands

Special Characters

• Comments (#)
• Line Endings (;)
• Empty Statements (:)
• Input/Output Redirection (>, <, >>)
• Output Redirection
• Input Redirection
• Pipes (|)
• Background Process Execution (&)

Variables and Parameters

• Variable Destruction (unset)
• Null Value Variables
• Assigning Results to Variables (backticks ``)
• Parameter Expansion ($0, $#,$1, $2, $3...)
• Manual Shift
• Quoting
• Escape Characters (\)

Regular Expressions

Conditional Statements

• The if/then construct
• The if/then/else construct
• Nesting If Statements
• The if/elif construct
• Case Statements
• Operators
• Logical Operators and, or (&&, ||)
• Test Command

Script Completion

The exit statement

Utilizing the program's exit status in a script ($?)

Tests and Operators

• Text File Operators
• File Type Tests
• File Attribute Tests

Comparison Operators

• Arithmetic Comparison Using If
• Integer Comparison Operators
• String Comparison
• Complex Comparisons (and, or)
• Nesting Comparison Operators
• Assignment Operator
• Arithmetic Operators
• Bitwise Operators
• Logical Operators
• Numeric Constants

Loops

• For/In Loop
• Seq Command
• While Loop
• Until Loop
• Loop Control (break, continue)

Text Processing

• Head, Tail Commands
• Sort, Uniq, Expand, Unexpand
• Cut, Paste, Join, Wc, Tr

Text Search (grep)

Stream Editor (sed)

Interactive Programs

• Read Command
• User Select

Features

Sleep Command

Troubleshooting: When Scripts Fail (Debugging)