The statement ends with the fi keyword. The CONSEQUENT-COMMANDS list that follows the then statement can be any valid UNIX command, any executable program, any executable shell script or any shell statement, with the exception of the closing fi. Let’s add an else clause to the previous example script: If you run the code and enter a number, the script will print a different message based on whether the number is greater or less/equal to 10.eval(ez_write_tag([[728,90],'linuxize_com-medrectangle-4','ezslot_0',160,'0','0'])); The Bash if..elif..else statement takes the following form: If the TEST-COMMAND1 evaluates to True, the STATEMENTS1 will be executed. The logic behind using the conditional “if” statement is the same in Bash as it is in any other programming language. Using if statement in bash. Sign up to our newsletter and get our latest tutorials and news straight to your mailbox. linux bash if statement inside for loop [duplicate] Ask Question Asked 5 years ago. It is important to remember that the then and fi are considered to be separated statements in the shell. Decision making is one of the most fundamental concepts of computer programming. Most people choose to use either 4-space or 2-space indentation. Here is another version of the script to print the largest number among the three numbers. In this version, instead of the nested if statements, we’re using the logical AND (&&) operator. If you have any questions or feedback, feel free to leave a comment. If the TEST-COMMAND2 evaluates to True, the STATEMENTS2 will be executed. Boolean Operations with Bash Scripts Therefore, when issued on the command line, they are separated by a semi-colon. Bash if elif Statement. When working with Bash and shell scripting, you might need to use conditions in your script.. For example, we ask the user to enter a … elif (else if) is used for multiple if conditions. Otherwise, if TEST-COMMAND returns False, the STATEMENTS2 will be executed. True if FILE exists and its sticky bit is set. If you like our content, please consider buying us a coffee.Thank you for your support! The Bash if..else statement takes the following form: If the TEST-COMMAND evaluates to True, the STATEMENTS1 will be executed. If you are not familiar yet (or would like to learn more about) Bash if statements, please see our Bash If Statements: If Elif Else Then Fi article. The following script will prompt you to enter three numbers and will print the largest number among the three numbers. There are different string operators available in bash scripting language which can be used to test strings. The Bash elif statement enables us deciding from more choices than two; as we have seen in the above case. The syntax for the simplest form is:Here, 1. To negate the test expression, use the logical NOT (!) The compact equivalent of the above test is as follows: Similar to the "&&" expression which indicates what to do if the test proves true, "||" specifies what to do if the test is false. When an IF statement is introduced in a bash script, it is intended to check for certain conditions before running different commands in the script. For example, if a user enters the marks 90 or more, we want to display “Excellent”. Note that, more than two conditions can be specified, for which elif statement can be used. In Bash, the test command takes one of the following syntax forms: To make the script portable, prefer using the old test [ command which is available on all POSIX shells. Bash If Statement with Bash, Bash Introduction, Bash Scripting, Bash Shell, History of Bash, Features of Bash, Filesystem and File Permissions, Relative vs Absolute Path, Hello World Bash Script, Bash Variables, Bash Functions, Bash Conditional Statements etc. Unary expressions are often used to examine the status of a file. In this guide, we will test these string operators using the if statement in Centos 8. If the decision to be made is a bit complex, multiple if statements will be needed. What is a Bash if else statement? If statements (and, closely related, case statements) allow us to make decisions in our Bash scripts. Bash IF. In a script, the different parts of the if statement are usually well-separated. This post should serve you as a cheat sheet to most of the scenarios that you might encounter in your everyday scripting tasks that uses conditional execution. The most compact syntax of the if command is: if TEST-COMMANDS; then CONSEQUENT-COMMANDS; fi. The ? In if-else statements, the execution of a block of statement is decided based on the result of the if condition.. Bash If-Else Statement Syntax AND operator returns true if both the operands are true, else it returns false. The condition in the if statement often involves a numerical or string test comparison, but it can also be any command that returns a status of 0 when it succeeds and some nonzero status when it fails. For example, input the marks of student and check if marks are greater or equal to 80 then print “Very Good”. Welcome guys to our 5 th tutorials in BASH scripting series (other tutorials are here). In this tutorial, we shall learn syntax of AND operator, and how to use Bash AND with IF statement, Bash AND with FOR loop. Firstly, what are Conditional statements ? The if construction allows you to specify such conditions. [ -s FILE ] True if FILE exists and has a size greater than zero. 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