BASH Programming Training Course

The simplest script

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

Calling the script

External and built-in commands

Special characters

• Comment (#)
• End of Line (;)
• Empty statement (:)
• Input/Output redirection (>, <, >>)
• Redirecting output
• Redirecting input
• Pipe (|)
• Running a process in the background (&)

Variables and Parameters

• Removing variables (unset)
• Variables with null values
• Storing results in a variable (backticks ``)
• Positional parameters ($0, $#, $1, $2, $3, etc.)
• Manual parameter shifting
• Quoting
• Escape character (\)

Regular Expressions

Conditional Statements

• The if/then structure
• The if/then/else structure
• Nesting if statements
• The if/elif structure
• Case statement
• Operators
• Logical operators AND (&&) and OR (||)
• test command

Script Termination

The exit statement

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

Tests and Operators

• 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
• The 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

Functions

sleep command

Troubleshooting (debugging)