Bash Math Functions

Introduction

• Overview of the video and its focus on basic math functions in Bash.
• This video is one of the shorter and easier ones in the series.

Handling Math in Bash

• Math functions in Bash differ from languages like Python.
  • Example in Python: 30 + 10 works directly.
  • In Bash, a different approach is required.

Evaluating Expressions with expr

• expr command is used to evaluate expressions in Bash.
• Example of addition:

  expr 30 + 10  
  

  • Output: 40

Basic Math Operations

• Addition:

  • Command: expr 30 + 10
  • Result: 40

• Subtraction:

  • Command: expr 30 - 10
  • Result: 20

• Division:

  • Command: expr 30 / 10
  • Result: 3

• Multiplication:

  • Command: expr 100 * 4
    • Important: Use backslash to escape the asterisk:

    expr 100 \* 4  
    

  • Result: 400
  • Explanation: Asterisk (*) is a wildcard in Bash.

Using Variables in Math

• Example of variable declaration and use in math:

  • Declare a variable:

    my_num1=100  
    

• Adding a number to a variable:

  expr $my_num1 + 50  
  

  • Result: 150

• Adding two variables together:

  • Declare another variable:

    my_num2=50  
    

  • Add them:

    expr $my_num1 + $my_num2  
    

  • Result: 150

Conclusion

• Recap of what was covered regarding basic math functions in Bash.
• Encouragement to check the next episode in the series.