BASH Programming Training Course

The simplest script

Selecting the shell (shebang #!)

Invoking the script

External and built-in commands

Special characters

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

Variables and Parameters

• Destroying variables (unset)
• Variables with null values
• Assigning results to variables (backticks ``)
• Parameter expansion ($0, $#,$1, $2, $3...)
• Manual shifting
• Quoting
• Escape characters (\)

Regular Expressions

Conditional Statements

• if / then
• if / then / else
• Nesting if statements
• if / elif
• case statement
• Operators
• Logical operators AND, OR (&&, | |)
• test command

Script Completion

The exit statement

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

Tests and Operators

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

Comparison Operators

• Arithmetic comparison using the if command
• Integer comparison operators
• String comparison
• Complex comparisons (AND, OR)
• Nesting comparison operators
• Assignment operators
• 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
• select command

Functions

sleep command

Troubleshooting: What if the script fails? (Debugging)