Bash Programming

Bash, a powerful programming language, is perfectly designed for command line and shell scripts. In this module, we’ll learn how to use Bash. Its features will help us solve our daily computer tasks and even automate some of them.

This module covers the general principles of computing operations and basic programming concepts in detail. It will also help us consolidate our new knowledge through exercises for each topic. Overall, this experience should be a great start to our Bash programming journey.

Basic Programming with Bash

## Arithmetic expressions
Bash allows us to do calculations on **integers**. We can apply the following operations: addition, subtraction, multiplication, and division. Besides that, Bash provides bitwise and logical operators. We will use them often when programming.


Bash does not support floating-point arithmetic. If we need this arithmetic in our scripts, we can use the [bc](https://en.wikipedia.org/wiki/Bc_(programming_language)) or [dc](https://en.wikipedia.org/wiki/Dc_(computer_program)) calculator.

## Integer representation

The first question we should consider is integers’ representation in the computer’s memory. This knowledge helps us understand mathematical operations in Bash.

We already know integers from mathematics. They do not have a fractional component and can be positive or negative. Programming languages with the static type system provide an integer type of variables. We should use this type whenever we need to operate on integers.

We can be very precise in programming and specify if the integer variable is positive only. The integer of this kind is called **unsigned**. If it is either positive or negative, the variable is called **signed**.

There are three common ways of representing integers in computer memory:


* **Sign-magnitude representation**(SMR)

* **One's complement**

* **Two's complement**


# Arithmetic expressions
Bash allows us to do calculations on **integers**. We can apply the following operations: addition, subtraction, multiplication, and division. Besides that, Bash provides bitwise and logical operators. We will use them often when programming.


Bash does not support floating-point arithmetic. If we need this arithmetic in our scripts, we can use the [bc](https://en.wikipedia.org/wiki/Bc_(programming_language)) or [dc](https://en.wikipedia.org/wiki/Dc_(computer_program)) calculator.

# Integer representation

The first question we should consider is integers’ representation in the computer’s memory. This knowledge helps us understand mathematical operations in Bash.

We already know integers from mathematics. They do not have a fractional component and can be positive or negative. Programming languages with the static type system provide an integer type of variables. We should use this type whenever we need to operate on integers.

We can be very precise in programming and specify if the integer variable is positive only. The integer of this kind is called **unsigned**. If it is either positive or negative, the variable is called **signed**.

There are three common ways of representing integers in computer memory:


* **Sign-magnitude representation**(SMR)

* **One's complement**

* **Two's complement**


Learn common ways of representing integers in computer memory.

Before We Begin

File System

Command Information

Bash Extra Features

Scripts Features

Variables and Parameters

Conditional Statements

Arithmetic Expressions and Operations

Bitwise Operations

Logical Operations and Increments

Loop Operators

Functions

Package Manager

Bash Programming from Scratch

Bash Scripts Tools

APPENDIX

Conclusion

Integer Representation

Arithmetic expressions