Conditional Statements

Name: Conditional Statements
Author: Jeremy Kurtz

Learn what conditional statements are and how to build and add on to them

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Course: On-Demand

In this lesson, we're going to look at conditional statements in Bash scripting. Conditional statements are actually little questions that exist inside of scripts and in programs. A question like is this number bigger than this number? And if it is, do this stuff. That English language model of conditional statements in Bash scripting is very accurate. So let's go ahead and create a new file and explore a couple of these conditions. So I'm gonna type nano, and then I'm gonna call this file cond for conditions. In fact, I'll even add a one. As I suspect, there'll be another. Once we're in here, we have to put the obvious information. And don't forget the path to the interpreter. Now that we have this, I'm going to introduce another command for us to use inside of shell scripting. That is the read command. So the first thing we're going to do is we're going to say echo Please enter a number. Now we wanna put the command in that allows the script to accept input from the user. That command is read. If we follow read with the name of a variable, for example, num, then it will take what the user input and apply it to that variable. And just because it's new for us, we're gonna go ahead and run this and echo it out to the screen. So we'll save it. And we'll make it executable. Let's clear the screen and run the script. It allows me to enter a number and I'll enter in 12. Notice then it echos 12 to the standard output. With that information, we can go back into nano, and now apply an if statement. Remember, the conditional operators associated with numbers are the letters. This is the syntax of our if statement. If, and now we're going to use the square brackets that are located to the right of the P key. Inside here, I'm going to say if num is less than, and we'll say 50. Then we add a semicolon. Then echo num1 is less than 50. And we can put in a \n to move us down to the next line. Now we can save this file. And clear the screen. And now we're going to run the file. Now we can enter a number. I'll purposefully enter one less than 50 to check our specific if statement. And it says num1 is less than 50. Let's run it one more time but this time, let's put in a number higher than 50. And notice it just prints the number and exits because we do not have anything to handle the other side of that coin. To handle the condition if it's not met is really just as important as handling the condition if it is met. So let's go back into nano and what we're going to do is we're going to add the else statement. So if it turns out that num is actually greater than 50, then we can go down here to right above the fi and we can say else echo num1 is greater than 50. Now let's give that a try. And now we can put in a number greater than 50 again, and you'll see that it now gets handled. This is a basic if-else statement inside of Bash scripting. In our next lesson, we are going to add multiple conditions. See ya then.

Advanced Provider : Jeremy Kurtz 6 Lessons · 40m in Arabic, German, English, Spanish, French, Portuguese, Chinese

Course Description

This course focuses on conditional statements in Bash. Conditional statements are little questions that exist inside of scripts and programs. Learn how to manage multiple conditions and adapt logical conditions to Bash scripting using conditional and looping structures.

What You'll Learn

Explore if-else and fi conditional statements in Bash
Apply elif to handle multiple conditions
Use the while loop and for loop structures in Bash scripting
Nest if statements within a loop
Work with ranges in for loops
Manage multiple logical conditions in Bash scripts

Key Takeaways

Conditional statements are little questions that exist inside of scripts and programs.
Bash supports if-else, fi, elif, while loop, and for loop conditional statements.
Logical conditions can be adapted to Bash scripting using conditional and looping structures.
If statements can be nested within loops to combine conditional logic with iteration.
For loops in Bash can operate over ranges.

Frequently Asked Questions

What does this course cover?

This course focuses on conditional statements in Bash, including if-else, fi, elif, the while loop, and the for loop, and teaches how to manage multiple conditions and adapt logical conditions to Bash scripting using conditional and looping structures.

What skills will I gain from this course?

You will gain skills in Bash (Scripting Language), Conditional Compilation, Conditional Expressions, Conditional Text, Conditional Statements, and Linux Scripting.

What lessons are included?

The lessons are: The If Else Fi Condition; Elif and Multiple conditions; The While Loop; Nesting If within a Loop; For Loops; and Ranges in For Loops.

Will I learn how to handle more than one condition?

Yes. The course teaches how to manage multiple conditions, including using elif for multiple conditions.