BASH Programming Training Course

Basic Script Structure

Specifying the Interpreter (Shebang Line)

Executing Shell Scripts

External and Built-in Commands

Special Syntax Characters

• Comments (#)
• Line Delimiter (;)
• No-Operation Command (:)
• Input/Output Redirection (>, <, >>)
• Output Redirection
• Input Redirection
• Pipes (|)
• Background Processes (&)

Variables and Parameters

• Variable Removal (unset)
• Handling Null Values
• Command Substitution (Backquotes)
• Positional Parameters ($0, $# , $1, $2, ...)
• Manual Parameter Shifting
• String Quoting
• Escape Sequences (\)

Regular Expressions

Conditional Logic

• If Statements
• If/Else Structures
• Nested Conditionals
• Elif Branches
• Case Statements
• Comparison Operators
• Logical Conjunctions and Disjunctions (&&, ||)
• Test Commands

Script Termination and Status

Exit Command Usage

Retrieving Process Exit Status ($?)

File Tests and Operators

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

Comparison Operators

• Arithmetic Comparisons within If Statements
• Integer Comparison Operators
• String Comparisons
• Compound Logical Comparisons
• Nested Comparison Expressions
• Assignment Operators
• Arithmetic Operators
• Bitwise Operations
• Logical Operators
• Numeric Constants

Loop Structures

• For/In Loops
• The seq Command
• While Loops
• Until Loops
• Loop Control (break, continue)

Text Processing

• Head and Tail Commands
• Sorting, Unique Filtering, and Tab Expansion
• Column Extraction, Merging, and Counting Tools

Pattern Search (grep)

Stream Editing (sed)

Interactive Script Features

• Read Command
• User Selection Prompts

Additional Utilities

Sleep Command

Troubleshooting and Debugging Scripts