BASH Programming Bash If-Then-Else Example. Bash if-else statement can be used in 3 different cases. They allow you to write code that runs only when certain conditions are met. Buy me a coffee. Bash Programming: Conditionals IF / ELSE Statements. If else is a conditional statement used in Bash scripting to execute different parts of your script based on the result of the if condition. If our condition is met, a block of code will be run; otherwise, another block of code will be run. They allow us to decide whether or not to run a piece of code based upon conditions that we may set. August 6, 2020 September 27, 2020 TECH ENUM. This statement is also used in bash to perform automated tasks like another programming language, just the syntax is a little bit different in bash. Once the Bash interpreter finds an if, else or elif statement, it continues the shell to let the user enter the code block. If marks are less than 80 and greater or equal to 50 then print 50 and so on. In Bash elif, there can be several elif blocks with a boolean expression for each one of them. The conditional statement is used in any programming language to do any decision-making tasks. We could do this by adding an else statement to our code: Let’s run our program again and try to insert the value 42: Our script now prints out a message when the user has failed their test. An if statement will evaluate whether a statement is true or false. Because it is unlike any other programming language. Otherwise, ' Block of Commands 1 ' is skipped and block of code under 'else', i.e. ' and if this case is true we will execute the COMMANDS, if not we will do not execute any … So the output will be Hy Aqsa Yasin in the terminal as shown in the below image. The TEST-COMMANDSlist is executed, and if its return status is zero, the CONSEQUENT-COMMANDSlist is executed. The if else statement is the way to make decisions in Bash scripting. We could make this happen using the following code: Let’s enter a student’s grade and tell our program that the student’s test has been peer reviewed: Now, let’s see what happens when we tell our program that a student’s test has not been peer reviewed who has earned the same grade (62): Because both of our conditions were not met – GRADE being over 50 and PEER_REVIEW being equal to “Y” – then the contents of our else statement were executed. In this article, we will learn Conditional … Block of Commands 1 ', is executed while ' Block of Commands 2 ' is skipped. In Bash, you can also use if…else, if…elif.else and nested if statements like other programming languages. By using the else operator, your if statement will execute a different set of statements depending on your test case. Sometimes, we want to process a specific set of statements if a condition is true, and another set of statements if it is false. If is another powerful tool in the Bash scripting tool box and has a very large number of uses. The following script will prompt you to enter three numbers and will print the largest number among the three numbers. To perform such type of actions, we can apply the if-else mechanism. How to use Bash else with if statement? If the result is true the code block will be executed, and if result is false program will bypass the code block. Else statements are run if none of the conditions you have specified in an if statement match. This question is a sequel of sorts to my earlier question.The users on this site kindly helped me determine how to write a bash for loop that iterates over string values. or any other programming Languages. For example, suppose that a loop control variable fname iterates over the strings "a.txt" "b.txt" "c.txt".I would like to echo "yes!" But here I have tried to pretty clearly … If-else is the decision making statements in bash scripting similar to any other programming. There’s no limit to how many if statements you can have inside your bash script. Moreover, the decision making statement is evaluating an expression and decide whether to perform an action or not. This is the most basic function of any conditional statement. Let’s try out our program by running bash script.sh: In this example, we’ve entered a grade greater than 50. Suppose we want to calculate a student’s letter grade based on their numerical grade. This article will introduce you to the five basic if statement clauses. The #!/bin/bash at the start specifies the interpreter to be used when the file is executed. For example, take 3 numeric values as input and check the greatest value. Bash If-Else Statement Syntax The syntax of the if-else statement in bash is: if [condition] then //if block code else // else block code fi If the condition evaluates to true, the if block code is executed, and if the condition evaluates to false then the … As a result, the code in our else statement was executed. If elif if ladder appears like a conditional ladder. Conditional Statements: There are total 5 conditional statements which can be used in bash programming. Introduction to If Else in Shell Scripting “If else” is a conditional or control statement in the programming language. You saw in the above example, no action is performed or any statement displayed when the condition was false. While you may only need to check for two conditions, there are plenty of cases where you may want to evaluate multiple different statements. This is important to note because using indents makes your code more readable, thereby reducing the chance that you make an error. We’ll never share your email address or … We want to assign the following letters based on a student’s grade: For this code, we are going to need to use an if, elif and else statements. The same example can be repeated for strings. It belongs to the ALGOL 60 family (Algorithmic Language 1960). Avoid intermixing them. You can place multiple if statement inside another if statement. If the resulting value is true , given statement(s) are executed. What’s more, if statements can be contained within themselves. When you’re writing a bash script, you may only want something to happen if multiple conditions are met, or if one of multiple conditions are met. If the expression evaluates to false, statements of else … Bash If Else : If else statement is used for conditional branching of program (script) execution in sequential programming. Otherwise, nothing will happen. If the condition you specify is met, then the code that comes after the “then” keyword will be executed. 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