BASH script "if then" with multiple conditions User Name: Remember Me? Introduction to Linux - A Hands on Guide This guide was created as an overview of the Linux Operating System, geared toward new users as an exploration tour and getting started guide, with exercises at the end of each chapter. We shall check if the number is even or if it also divisible by 5. If the condition is true, the commands following the, echo “Sorry, you are not allowed to be here, you are too young!”, First, we ask a user to enter his/her age. The ‘if COMMANDS‘ list is executed.If its status is zero, then the ‘then COMMANDS‘ list is executed.Otherwise, each ‘elif COMMANDS‘ list is executed in turn, and if its exit status is zero, the corresponding ‘then COMMANDS‘ list is executed and the if command completes. echo “Sorry, you are not allowed to be here, you are too young!” -ne – not equal to Notices: Welcome to LinuxQuestions.org, a friendly and active Linux Community. NOT operator. read age The name stands for Global Regular Expression Print. Learn How to Properly Run Subshells Using Bash Scripts. Logical OR& ANDoperations are very useful where multiple conditions are used in our programs (scripts). echo “You are too old! And as per the previous comments, when using bash or ksh, it's recommended to use ((..)) for numerical tests, and [[..]] for string/file tests and complex expressions. Sometimes we only want to do something if multiple conditions are met. 1 Syntax. message is displayed: Here is a list of all comparison operators: -eq – equal to fi. If it isn't true do, that. Let’s say that we want to test if a file exists, and then execute different commands based upon that condition. But to print the lines when all the provided PATTERN match, we must use AND operator. The number that the user has entered is then assigned to the variable, echo “You are just the right age. Foxes are wild animals. Learn Unix relational operators and conditional statements like … then A logical condition is created, when two or more conditioned produce a single result based on them. Hello World: Your First Raspberry Pi Project. These operators combine several true/false values into a final True or False outcome (Sweigart, 2015). Leave now! Let’s say that we want to find out the user’s age. Using grep -e option you can pass only one parameter. -ge – greater than or equal to. By default when we search for a pattern or a … The basic structure of the if statement looks like this: if [ conditional-expression ] then commands else other-commands fi. || is the operator used for AND boolean operation. In the second parameter, type the value that you want Excel to display if the condition is true. These options are used for file operations, string operations, etc. Go away!” OR logical operator combines two or more simple or compound conditions and forms a compound condition. Grep is a powerful utility available by default on UNIX-based systems. The first score, stored in column C, must be equal to or greater than 20. Syntax: test EXPRESSION. exit status: 0 Both integers are not equal . (3 Replies) 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. Welcome!” Use multiple -e options in a single command to get multiple patterns to implement OR operations. How to Use the Linux Sleep Command to Pause a BASH Script . fi. If marks are less than 80 and greater or equal to 50 then print 50 and so on. Syntax of OR Operator. Search for multiple patterns with AND condition. Here, 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. We can ask a user to enter his or her age, and then execute different commands, depending on the input: #!/bin/bash Check the below script and execute it on the shell with different-2 inputs. OR logical operator combines two or more simple or compound conditions and forms a compound condition. By using the grep command, you can customize how the tool searches for a pattern or multiple patterns in this case. /bin/bash You can grep multiple strings in … If statement can accept options to perform a specific task. A Simple if Condition. if [ “$age” -ge 21 ] ; then If there is a command-sequence that should optionally run based on whether a conditional expression is true, then the if/then statement can look as simple as this: if [[some condition ]]; then do_something fi. I am analyzing one of the scripts written by another person.script is having multiple if conditions and everything are nested.The code is not formatted properly.Is there any way to identify in Unix to identify begin and end of a particular if block? The syntax would be: Here one condition result may also invert the result of a other condition. Otherwise, the commands following the else keyword are executed. other-commands To demonstrate if-then-else statement examples, I am using the text file named foxfile.txt, which stored in the folder /home/vin/test and the following are the contents of this file: foxfile.txt A quick brown Fox jumps right over the lazy dog. Syntax : -f – file exists and is not a directory Linux if-then-else Condition Shell Script Examples. grep -e pattern1 -e pattern2 filename. elif (else if) is used for multiple if conditions. -r – file is readable, One of the most commonly used programming constructs is the conditional execution, or the, First, the condition inside the brackets is evaluated. Welcome! Use multiple -e option in a single command to use multiple patterns for the or condition. How to Use the IF … Recent Posts. First, the condition inside the brackets is evaluated. Multiple Conditions # The logical OR and AND operators allow you to use multiple conditions in the if statements. Welcome!” As an alternative, we can use the elif construct , shot for else if. else First, we ask a user to enter his/her age. When you will be doing some complex data analysis, you might be needed to analyze more than one conditions at a time. Welcome! Search multiple patterns with awk . [me@linux ~] $ touch myfile [me@linux ~] $ if [[-f myfile &&-r myfile ]]; then echo "File exists and is Readable. The question does not have to be directly related to Linux and any language is fair game. 2. bash my-script.sh 90210 – then my-script.sh has access to the value 90210 by referring to $1 (and if a second argument was passed in, it'd be inside $2) Just an if-statement. In this article, we are going to tackle very important topic: the test conditions. We can nest if statement , allowing for multiple conditions. Name Email Website. Awk Text Split and Delimit Examples. read age As we mentioned above, you can use the binary operators && (and) and | | (or) in the double brackets [[compound notation. First, the condition inside the brackets is evaluated. ©Copyright-Tutorialkart 2018, # and opertor used to carry out certain commands based upon that condition compound.. A final true or not is given to a Bash script how use. 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