Dies ist auf alle Syntax-Arten von IF anwendbar. Aus irgendeinem Grund habe ich lange Zeit nicht gewusst, dass es If Else in Batch gibt… Ich hatte bereits ein Tutorial zum Kombinieren mehrerer Befehle in einer Zeile geschrieben. else statement3 statement4 . Damit kann ich so etwas wie If Else vortäuschen: if not 0==1 echo dies & echo das & del jenes.txt & goto korrekt echo foo & […] In this chapter of bash beginner series, you'll learn about using if-else, nested if else and case statements in bash scripts.In this part of the bash beginner series, you will learn how to use conditional statements in your bash scripts to make it behave differently in different scenarios and cases. 1.1 if/then/else Example.

When working with Bash and shell scripting, you might need to use conditions in your script.. The general syntax of a case construct is as follows:Case statements are particularly useful when dealing with pattern matching or regular expressions. Indentations and blank lines make your code more readable and organized.Save the code in a file and run it from the command line:The script will prompt you to enter a number.

The script will prompt you to enter a number.

Check your inbox and click the link to complete signin If there are no arguments or more than one argument, the script will output a message and exit without running rest of the statements in the script.Let’s do a few runs of the script to test it with various types of files:So far all the if else statement you saw were used in a proper bash script. If, for example, you enter 15, the test command will evaluate to true because 15 is greater than 10, and the echo command inside the then clause will be executed.

The shell first evaluates condition 1, then condition 2, and so on, stopping with the first condition that succeeds. Let’s do a few runs of the script to see how it works:You can also use case statements in bash to replace multiple if statements as they are sometimes confusing and hard to read.

This way you can build much more efficient bash scripts and you can also implement error checking in your scripts.The most fundamental construct in any decision-making structure is an if condition.

After the execution of if/else part, execution resume with the consequent statements.
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That's the decent way of doing it but you are not obliged to it.When you just want to see the result in the shell itself, you may use the if else statements in a single line in bash.You can use all the if else statements in a single line like this:You can copy and paste the above in terminal and see the result for yourself.Basically, you just add semicolons after the commands and then add the next if-else statement.Awesome!

For example, find out if file exists (true condition) or not (false condition) and take action based on a condition result. You can also use an if statement within another if statement. Bash If..then..else..fi statement If [ conditional expression ] then statement1 statement2 . The statements associated with that successful condition are then executed, followed by any statements after the fi statement. Also not, [[is indeed a Bash keyword, but in this case it's only parsed as a normal command argument, because it's not at the front of the command. In this version, instead of the nested To make the script portable, prefer using the old test Below are some of the most commonly used operators:If you have any questions or feedback, feel free to leave a comment.If you like our content, please consider buying us a coffee.Sign up to our newsletter and get our latest tutorials and news straight to your mailbox.

Any code you want to run when an if condition is evaluated to false can be included in an else statement as follows: #!/bin/bash if [ $(whoami) = 'root' ]; then echo "You are root" else echo "You are not root" fi . share | improve this answer | follow | edited Jun 20 at 9:12. If the conditional expression returns zero, it jumps to else part, and executes the statement3 and 4. ELSE: wird ausgeführt, wenn die Bedingung nicht erfüllt wird.Im ELSE-Teil kann ein weiterer IF-Befehl durchgeführt werden. The general syntax of a basic if statement is as follows:Don't believe me? Most people choose to use either 4-space or 2-space indentation.