Operators

Name: Operators
Author: Jeremy Kurtz

Discover comparisons in Bash, how strings are tested, and how math operators function

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Course: On-Demand

In this lesson, we're going to talk about Comparison Operators in Bash Scripting. This is a very simple lesson. This is more about learning how Bash handles any type of comparison. So in mathematics, we talk about something greater than something else, less than, equal to, not equal to. Those all exist in Bash scripting. The difference, however, is that strings are treated differently than numbers. So let's just go over them. I'm going to go ahead and create a file in nano called operators. While we're in here, we can now take a look at how strings are tested. Now we're not talking about testing yet. That's coming in a different lesson. But if we're in a position to compare two things, we need to know how to do that syntactically. In the world of strings, we actually use a lot of the same operators as we do in middle school math. For example, to say something is equal to, we would use two equal signs. The reason we use two is because a single equal sign is used as an assignment operator. So if I have a variable and I want to assign it a number, I would say something like a number, and then equals singular 10. If I was testing my variable against another number, I would use two equal signs. So I'm asking or saying if number equals 10. So that's the difference between a single and a double equal sign. In fact, that only happens in these types of cases. Everything else is pretty standard to what we've learned. So we have greater than, we have less than, we have greater than or equal to, we have less than or equal to, we also have not equal to which is an exclamation point followed by an equal sign. That is how strings are handled. Now there's two other operators for strings that we want to consider, and these are Boolean Conditional Operators. So if I have a variable and I wanna test the variable to see if it's populated by something, I would use dash lowercase n. This means is not null. If we wanna test to check to see if it's empty, we would say -z and that equals is the variable empty. Those are the conditional operators for strengths. If we're doing it with numbers, so if I'm comparing two numbers, I would use -eq for if they are equal. If I use -ne that's not equal. gt is greater than -lt is less than. Then if we want to use greater than or less than or equal to, we would merely do -ge which means greater than or equal to -le or less than or equal to. In our next lesson, we're going to talk about mathematical operators. See you then.

Advanced Provider : Jeremy Kurtz 3 Lessons · 22m in Arabic, German, English, Spanish, French, Portuguese, Chinese

Course Description

This course will explore comparisons and operators in Bash. Learn how Bash handles comparisons and uses mathematical operations. Apply math, equality, and comparison operators in a Bash script.

What You'll Learn

Understand how comparisons exist and are handled in Bash
Compare strings by testing them in Bash
Apply comparison operators in a Bash script
Use math operators to perform mathematical operations in Bash
Apply equality operators within Bash scripts

Key Takeaways

Bash provides operators for performing comparisons within scripts.
Strings in Bash can be tested in order to compare them.
Bash supports math operators that carry out mathematical operations.
Math, equality, and comparison operators can be applied directly in a Bash script.

Frequently Asked Questions

What does this course cover?

It explores comparisons and operators in Bash, including how Bash handles comparisons and uses mathematical operations, and how to apply math, equality, and comparison operators in a Bash script.

What lessons are included in this course?

The course includes three lessons: Comparison Operators, Math Operators Part 1, and Math Operators Part 2.

What skills will I gain from this course?

The course covers skills including Bash scripting, Linux scripting, logical operators, operands, operators in C and C++, and shell script.

Will I learn how strings are compared in Bash?

Yes, one of the learning objectives is to learn how strings are tested to compare in Bash.