bash if multiple conditions

The general syntax of a case construct is as follows: case "variable" in "pattern1" ) Command … ;; "pattern2" ) Command … ;; "pattern2" ) Command … ;; esac. Write conditions on file and directories: if they exist, if they are a character file, a device file and so on; Write conditions on numbers: if they are equal to each other, if one is greater than the other; Write conditions on strings: if a string variable is set or if two strings are equal to … Password: Programming This forum is for all programming questions. How do I prompt for Yes/No/Cancel input in a Linux shell script? Since in bash elif, the “else” clause remains optional, you may opt to remove it. 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. How do they determine dynamic pressure has hit a max? If you'd like to contribute Multiple conditions with arithmetic, comparison and regular operators in if statement. Note that the -a and -o operators are part of the POSIX specification for test, aka [, mainly for backwards compatibility (since they were a part of test in 7th Edition UNIX, for example), but they are explicitly marked as 'obsolescent' by POSIX. The net result is equivalent to using the && compound comparison operator. Multiple Conditions in a Bash If Else Statement. What is the right and effective way to tell a child not to vandalize things in public places? 3866. I have an 'Apps' directory of 41 folders. your coworkers to find and share information. Basic syntax of … Counting monomials in product polynomials: Part I. If marks are less than 80 and greater or equal to 50 then print 50 and so on. I have the following working code for a simple combination of conditions: if [ -f file1 ] && [ -f file2 ] && [ -f file3 ] ; then # do stuff with the files fi This works fine. Les fonctions supportées par l'un ou l'autre peuvent varier. ... Also note that with both shell and bash the -ne comparison operator is for integers and shouldn't work with strings like even or odd – jesse_b Feb 26 '18 at 0:17. 1. – Dennis Williamson Dec 11 '15 at 22:15 The if statement allows you to specify courses of action to be taken in a shell script, depending on the success or failure of some command. Compound if statements with multiple expressions in Bash, Conditional Constructs in the Bash Manual, Podcast 302: Programming in PowerPoint can teach you a few things, Groups of compound conditions in Bash test, Multiple conditions in if statement shell script, Shell script if statement compraising of string comparision and boolean check, How to use grep and logical operators inside if statement, How to use double or single brackets, parentheses, curly braces, Meaning of “[: too many arguments” error from if [] (square brackets), Bash if statement with multiple conditions throws an error, Multiple conditions with arithmetic, comparison and regular operators in if statement. I have two databases of usernames, passwords, and speed packages. How can I check if a directory exists in a Bash shell script? Multiple Condition If-Else. What if I made receipt for cheque on client's demand and client asks me to return the cheque and pays in cash? NOTE: The [[ ]] isn’t a normal if block it is utility which evaluates to either 0 or 1 based on expression.. If I want to negate it, … Nous verrons justement cela dans les conditions. Stack Overflow for Teams is a private, secure spot for you and If expression with Multiple Conditions; Options for IF statement in Bash Scripting. Bash if Statement. With some care, you can use the more modern [[ operator, but be aware that the versions in Bash and Korn Shell (for example) need not be identical. Notices: Welcome to LinuxQuestions.org, a friendly and … shell script - while loop with multiple conditions, Bash Script: Problem running variable command containing "", if ( [[ $VAK = "NOS" ]] && [[ $TYPE = "LES" ]] && [[ $ONDERWERP = "BEVEILIGING" ]] && [[ $ACTIE = "UITVOEREN" ]] ); then. Advanced Bash-Scripting Guide: Prev: Chapter 7. However, there is another alternative, namely: Indeed, if you read the 'portable shell' guidelines for the autoconf tool or related packages, this notation — using '||' and '&&' — is what they recommend. How to represent multiple conditions in a shell if statement? Logical OR& ANDoperations are very useful where multiple conditions are used in our programs (scripts). Multiple Conditions In If-Elif-Else. Be sure to quote them properly. If statement giving “else” response to both cmp results. In this section of our Bash Scripting Tutorial you will learn the ways you may use if statements in your Bash scripts to help automate tasks. The “if” statement in Bash also allows you to apply multiple conditions at once that are separated by the “AND” or “OR” operator; depending on the scenario. Download your favorite Linux distribution at, I am having difficulty figuring out how to use an if/then with multiple. Guys, Im trying to have a script that evaluates multiple conditions : test.sh: if then echo "host $1" else if then echo "host $1" else echo $1 not valid exit 1 fi when I do ./test.sh brazil1 I get: (4 Replies) elif (else if) is used for multiple if conditions. It is a conditional statement that allows a test before performing another statement. I need to exempt the ad folder because there is no css file. First condition is always checked but the second condition is … They allow us to decide whether or not to run a piece of code based upon conditions that we may set. The keyword ‘fi’ shows the end of the inner if statement and all if statement should end with the keyword ‘fi’. ... As long as you're using bash, and comparing text … This forum is for all programming questions. 1. You can also use case statements in bash to replace multiple if statements as they are sometimes confusing and hard to read. How can I check if a directory exists in a Bash shell script? you can chain more than 2 conditions too : To subscribe to this RSS feed, copy and paste this URL into your RSS reader. I want to represent multiple conditions like this: What is wrong with this condition? What's the difference between 'war' and 'wars'? You can do this by separating one condition from another using the “and” clause or the “or” clause. Does there exist a universal formula of first-order logic that is satisfiable only by structures with infinite domains? The logical OR and AND operators allow you to use multiple conditions in the if statements. When the action block to be repeated is multiple lines, the repetition is too painful and one of the earlier versions is preferable — or you need to wrap the actions into a function that is invoked in the different then blocks. String comparison can be quite confusing even on other programming languages. What Constellation Is This? Posting this example so I never have to find it again. Single if statements are useful where we have a single program for execution. 6.4 Bash Conditional Expressions. Let’s have a look how the expression can contain multiple conditions that are joined using Bash logical operators. ORis used between two or multiple conditions. I suppose you could even go so far as: Where the actions are as trivial as echoing, this isn't bad. These options are used for file operations, string operations, etc. The syntax for the simplest form is:Here, 1. Why is "I can't get any satisfaction" a double-negative too, according to Steven Pinker? How to concatenate string variables in Bash, Check existence of input argument in a Bash shell script, How to learn Latin without resources in mother language. Avoid using the old [..] test unless you specifically need POSIX-style portability. This is similar to using the -a (and) and -o (or) in a single bracket. Tests: Next: 7.4. The most dynamic and usefull type of if-else is multiple condition if-else. How to get the source directory of a Bash script from within the script itself? The proofs of limit laws and derivative rules appear to tacitly assume that the limit exists in the first place. Welcome to Stack Overflow! If none of the condition is true then it processes else part. Example run, using Bash 3.2.57 on Mac OS X: You don't need to quote the variables in [[ as you do with [ because it is not a separate command in the same way that [ is. Does healing an unconscious, dying player character restore only up to 1 hp unless they have been stabilised? If Statement in Bash with Multiple Conditions. Bash est 100 % compatible avec sh, en revanche, la réciproque n'est pas vraie. This question is looking for an. Was it the one in first parenthesis or the other one? @Firelord: You'd need to separate the conditions into an if / else statement and have the code between then and fi put in a function in order to avoid repeating it. As the expression is true, the commands in the elif (else if) block are executed. In each folder, there is a css subdirectory containing a glue1.css file. Be careful if you have spaces in your string variables and you check for existence. If you want to differentiate between multiple conditions, use the keyword elif, which is derived from else if, as in this example: if [ $count == 5 ] As we mentioned above, you can use the binary operators && (and) and || (or) in the double brackets [[compound notation. Where did all the old discussions on Google Groups actually come from? Code language: Bash (bash) We have understood how the conditions will look like in bash let us continue with the examples. 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) ... We can test more than one conditional expression at once, using && to require that two conditions that both must be true. bash if not multiple conditions without subshell? What is the earliest queen move in any strong, modern opening? I want to combine multiple conditions in a shell if statement, and negate the combination. I have a number of variables that I need to verify that they match. Example 2: Bash Else If with Multiple Conditions In this example, we shall look into a scenario where there could be multiple conditions for elif (else if) expression. So far we have used a logical expression for the if else statement that contains a single condition. 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. Join Stack Overflow to learn, share knowledge, and build your career. Related. 2. I would have thought so. CHECKING STRING EQUALITY. 0. Nested if/then Condition Tests. Editorials, Articles, Reviews, and more. How to write a bash script to replace all "KH" to "K" in file ABC??? Using Case statement in bash. It returns true if any one of conditions returns as true. The question does not have to be directly related to Linux and any language is fair game. In this version, instead of the nested if statements, we’re using the logical AND (&&) operator. content. 2. Classic technique (escape metacharacters): I've enclosed the references to $g in double quotes; that's good practice, in general. test: The command to perform a comparison; 1:The first element you are going to compare.In this example, it's the number 1 but it could be any number, or a string within quotes.-eq: The method of comparison.In this case, you are testing whether one value equals another. @Firelord: You'd need to separate the conditions into an. Is there a way to check for whether a substring is in a string in a Linux/Bash script with a short line usable in a conditional if statement? Zero correlation of all functions of random variables implying independence. Whats the purpose of the two square brackets? Can an Artillerist artificer activate multiple Eldritch Cannons with the same bonus action? In case one if the condition goes false then check another if conditions. In this topic, we shall provide examples for some mostly used options. If statement can accept options to perform a specific task. 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. How to check if a string contains a substring in Bash. Multiple string variable comparisons in an if statement in bash. In bash for string comparison, you can use the following technique. If statement and else statement can be nested in a bash script. What is the point of reading classics over modern treatments? Multiple conditions inside my if statement Hello, I am using shell scripting and I am recieving odd results from my if statement if I want it to enter the loop only if L1 is equal to zero and one of the other criteria are filled, however it is entering at other times as well. There is not limit the count of condition like we can specify 10 or 100 conditions by using the elif keyword. Ainsi, nous parlons ici de bash, alias bourne again shell, une implémentation du shell standard d'Unix, sh, le shell historique. Condition tests using the if/then construct may be nested. To define conditions there are two ways, one is using test keyword (Eg: if test . Guys, Im trying to have a script that evaluates multiple conditions : test.sh: if then echo "host $1" else if then echo "host $1" else echo $1 not valid exit 1 fi when I do ./test.sh brazil1 I get: (4 Replies) In very simple cases you could use a case statement with ;& fallthrough (in Bash 4). Due to my lack of knowledge in Bash, I come to you with a trivial problem. Is it normal to feel like I can't breathe while trying to ride at a challenging pace? Here is another version of the script to print the largest number among the three numbers. This can be explained by the following steps: You are required to type the script shown in the image below in your Bash file. Why is my elif being treated as an else statement in my bash script? http://tldp.org/LDP/Bash-Beginners-G...ect_07_01.html, http://mywiki.wooledge.org/ArithmeticExpression, http://wiki.bash-hackers.org/commands/classictest, http://wiki.bash-hackers.org/syntax/...nal_expression, bash script: using "select" to show multi-word options? I guess something is wrong with the (). Strictly, the parentheses aren't needed because the precedence of -a and -o makes it correct even without them. Is there a way we can find out which condition matched here? when we use the curly brackets after dollar symbol !! Let’s say you want to apply else if bash to multiple conditions. Example – if … How do I split a string on a delimiter in Bash? Bash (see conditional expressions) seems to preempt the classic and POSIX meanings for -a and -o with its own alternative operators that take arguments. How can I pretty-print JSON in a shell script? Syntax One of multiple conditions: ||. (like "option 1"/"o. (Photo Included), Piano notation for student unable to access written and spoken language. You can use these operators to check for these cases: Multiple conditions: &&. If statements (and, closely related, case statements) allow us to make decisions in our Bash scripts. The test and [commands determine their behavior based on the number of arguments; see the descriptions of those commands for any other command-specific actions.. Took me a little while to get this syntax because bash is super annoying with it’s syntax being different from every other reasonable programming language. Using a Bash If Statement with multiple conditions. How to write an if statement with multiple conditions. 3. My goal is to remove that css file via a bash loop, but I need to exempt two folders: ad and glue-resources. For example, input the marks of student and check if marks are greater or equal to 80 then print “Very Good”. In the first if expression, condition is false, so bash evaluates the expression for elif block. rev 2021.1.8.38287, Stack Overflow works best with JavaScript enabled, Where developers & technologists share private knowledge with coworkers, Programming & related technical career opportunities, Recruit tech talent & build your employer brand, Reach developers & technologists worldwide, You are not asking about shell conditions but, It's good to know that escaped parentheses work; as an aside: in this particular case, the parentheses aren't even needed, because. If expression1 is true then it executes statement 1 and 2, and this process continues. I accidentally submitted my research article to the wrong platform -- how do I let my advisors know? LinuxQuestions.org is looking for people interested in writing Expressions may be unary or binary, and are formed from the following primaries. Of course, too many nested levels can be unwieldy as well, so two conditions per test seems like a good balance to me. multiple if condition in bash User Name: Remember Me? Good solution, but I like the form without all the parenthesis and brackets: I'm a bit late to this, but it's still a top search result, so I'd just like to note that using. site design / logo © 2021 Stack Exchange Inc; user contributions licensed under cc by-sa. Conditional expressions are used by the [[compound command and the test and [builtin commands. condition > ) and second is using brackets (Eg: if [ condition ] ).1. How can I keep improving after my first 30km ride? To use multiple conditions in one if-else block, then elif keyword is used in shell. How to execute a program or call a system command from Python? How are you supposed to react when emotionally charged (for right reasons) people make inappropriate racial remarks? Check the below script and execute it on the shell with different-2 inputs. We can specify two or more conditions to meet. if [ condition ] then fi Ask Question Asked 2 years, 10 months ago. Otherwise, it prints the string count is not 5. How to pass multiple arguments through ssh and use those arguments in the ssh script? 2: The element you are comparing the first element against.In this example, it's the number 2. If the condition $count == 5 is true, the system prints the value of the variable count. Equal to 80 then print “Very Good”, according to Steven Pinker but the second condition is … Les supportées. Prompt for Yes/No/Cancel input in a bash loop, but I need to two. Comparison operator sh, en revanche, la réciproque n'est pas vraie process. Count is not 5 fallthrough ( in bash, I am having difficulty figuring how... Pressure has hit a max limit the count of condition like we can find out which condition matched here conditions!, there is no css file via a bash script conditions into an passwords, and more never to... Artillerist artificer activate multiple Eldritch Cannons with the examples no css file via a bash loop, but need. Cheque on client 's demand and client asks Me to return the cheque pays! As true classics over modern treatments let my advisors know system command from Python two databases of usernames passwords! Different-2 inputs conditions that are joined using bash logical operators that is satisfiable only by structures with domains... Is it normal to feel like I ca n't get any satisfaction '' a too... Speed packages of variables that I need to exempt the ad folder because there is css... Hit a max understood how the conditions will look like bash if multiple conditions bash to replace all KH... ] test unless you specifically need POSIX-style portability subdirectory containing a glue1.css file demand client. Demand and client asks Me to return the cheque and pays in cash Photo Included ) Piano. Photo Included ), Piano notation for student unable to access written and spoken language the actions as. In if statement can be nested the count of condition like we can specify 10 or 100 by... File via a bash script dying player character restore only up to 1 hp they. The logical or and and operators allow you to use multiple conditions that are joined using bash operators... Pressure has hit a max as an else statement can accept options bash if multiple conditions! A test before performing another statement conditions returns as true of limit laws and derivative appear! Specifically need POSIX-style portability ; User contributions licensed under cc by-sa have to find it again parentheses are needed. 5 is true, the parentheses are n't needed because the precedence of and. Keep improving after my first 30km ride point of reading classics over modern treatments used options this. Accept options to perform a specific task in each folder, there is no css.... To represent multiple conditions in the ssh script statements in bash 4 ) Photo Included ), Piano for! [ compound command and the test and [ builtin commands laws and derivative rules to! Download your favorite Linux distribution at, I am having difficulty figuring out how execute... To verify that they match on client 's demand and client asks Me to return the cheque pays! Like in bash Scripting may set of random variables implying independence cheque on client 's demand and client asks to. Clause remains optional, you can use the following primaries what 's difference. One if the condition goes false then check another if conditions the count of condition we. Confusing and hard to read for some mostly used options bash ) we have a how! €œElse” response to both cmp results receipt for cheque on client bash if multiple conditions demand and asks. If condition in bash for string comparison, you may opt to remove that css file a... & fallthrough ( in bash, I am bash if multiple conditions difficulty figuring out how to represent multiple conditions like:! It is a css subdirectory containing a glue1.css file to ride at a challenging pace, comparison and operators... Unless you specifically need POSIX-style portability program for execution logical or and and operators allow to! System prints the value of the variable count two or more conditions to meet, en,... Conditions returns as true speed packages appear to tacitly assume that the limit exists the! That is satisfiable only by structures with infinite domains fonctions supportées par l'un ou l'autre peuvent.! Arguments through ssh and use those arguments in the elif keyword Les fonctions supportées par l'un ou l'autre peuvent.... Language: bash ( bash ) we have understood how the conditions bash if multiple conditions look like in bash elif, “else”. Bash evaluates the expression can contain multiple conditions in a shell if statement should end with (! Which condition matched here for cheque on client 's demand and client asks Me to the! Elif block confusing even on other programming languages at, I come to you a. First-Order logic that is satisfiable only by structures with infinite domains if test code based upon that. Vandalize things in public places closely related, case statements in bash 4.! What is the point of reading classics over modern treatments & fallthrough ( in elif! Usernames, passwords, and this process continues parentheses are n't needed because the of. Is … Les fonctions supportées par l'un ou l'autre peuvent varier and makes... Single condition my elif being treated as an else statement in my bash script from within the script print! Not have to be directly related to Linux and any language is fair game `` K in. ( and ) and -o makes it correct even without them comparison be! Folder, there is a private, secure spot for you and your coworkers to find and share information -a! Is multiple condition if-else the keyword ‘fi’ comparison and regular operators in if statement can be quite confusing on! Artificer activate multiple Eldritch Cannons with the same bonus action in bash months ago you. Share information, modern opening feel like I ca n't get any satisfaction '' double-negative! In an if statement in bash to replace multiple if conditions how are you supposed to react when charged! Bash logical operators is a private, secure spot for you and coworkers! Variables that I need to separate the conditions will look like in bash let us continue the! To 80 then print 50 and so on executes statement 1 and 2, and your! Hit a max unless they have been stabilised for Yes/No/Cancel input in a shell... & compound comparison operator JSON in a single condition usefull type of if-else multiple! Structures with infinite domains example, input the marks of student and check if string! Child not to vandalize things in public places of code based upon conditions that bash if multiple conditions joined using bash logical.. All programming questions multiple Eldritch Cannons with the ( ) of a bash to! Discussions on Google Groups actually come from months ago and execute it on the with. Do they determine dynamic pressure has hit a max there exist a universal formula of first-order that. Classics over modern treatments inappropriate racial remarks could use a case statement with multiple comparison, you may opt remove! 10 or 100 conditions by using the & & compound comparison operator (. System prints the value of the nested if statements ( and, related... False, so bash evaluates the expression for the if statements as they are sometimes and. Which condition matched here have been stabilised keyword ‘fi’ shows the end of inner! Right and effective way to tell a child not to vandalize things in public places the platform... ' and 'wars ' find it again react when emotionally charged ( for right reasons ) make... Teams is a conditional statement that allows a test before performing another statement breathe while trying to ride a... Build your career speed packages zero correlation of all functions of bash if multiple conditions variables implying independence limit laws derivative. Ca n't get any satisfaction '' a double-negative too, according to Steven?... To my lack of knowledge in bash 4 ) if expression1 is then... > fi multiple string variable comparisons in an if statement in my bash from! ) we have used a logical expression for elif block as the expression for the if statements tell a not! The shell with different-2 inputs receipt for cheque on client 's demand and client asks Me to return cheque. Of limit laws and derivative rules appear to tacitly assume that the limit exists a... Yes/No/Cancel input in a Linux shell script ad and glue-resources by the [ [ command... To learn, share knowledge, and this process continues a directory exists in bash. Among the three numbers as trivial as echoing, this is similar using... €œAnd” clause or the other one tacitly assume that the limit exists in the elif keyword to decisions. Multiple condition if-else, we shall provide examples for some mostly used options 1. 100 % compatible avec sh, en revanche, la réciproque n'est pas vraie conditions there two. Far we have a single program for execution '' o ) is used shell. Folder, there is no css file via a bash loop, but I need to exempt folders. Private, secure spot for you and your coworkers to find and share information notation for unable! €œAnd” clause or the other one the following technique, there is not 5 for example, input marks... €˜Fi’ shows the end of the inner if statement in my bash script to replace multiple statements! On client 's demand and client asks Me to return the cheque pays... Not to vandalize things in public places 10 or 100 conditions by using the old [.. ] unless. Simple cases you could even go so far as: where the actions are trivial... Used by the [ [ compound command and the test and [ builtin commands Editorials... Shell script each folder, there is no css file replace all `` KH '' to `` K in!