BASH Programming Training Course

The simplest script

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

Executing the script

External and built-in commands

Special characters

• Comments (#)
• End of Line (;)
• Empty statement (:)
• Redirection of input output (>, <, >>)
• Redirecting output
• Redirection of input
• Stream (|)
• Running processes in the background (&)

Variables and Parameters

• Unsetting variables (unset)
• Variables with null values
• Storing results in variables (backquotes ``)
• Parameter requests ($ 0, $ #, $ 1, $ 2, $ 3 ...)
• Manual shifting
• Quoting.
• Escape character (\)

Regular Expressions

Conditional statements

• The if / then structure
• The if / then / else structure
• Nested if statements
• The if / elif structure
• case statements
• Operators
• Logical operators and, or (&&, | |)
• test command

Script Completion

The exit statement

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

Tests and Operators

• Text file operators
• 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
• The assignment operator
• 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
• Cut, Paste, Join, Wc, Tr

Text search (grep)

Stream Editor (sed)

Interactive programs

• Read command
• User selection

Features

Sleep command

Troubleshooting non-functional scripts (debugging)