Bash variable with double quotes. " (in EXPANSION > Command Substitution).

Bash variable with double quotes It removes the quotes from the string that is held by a variable. Your shell is not passing the quotes through to the script. The end result I'm after is for my script to call: lwp-request -U -e -H "Range: bytes=20-30" My script file looks like: In shell scripts, when do we use {} when expanding variables? For example, I have seen the following: Jun 17, 2020 · If you want to store in an array the list of files resulting from the expansion of a glob pattern stored in variable, in bash, that would be: pattern='path with wildcard*' Jan 13, 2020 · I have a bash script where i'm trying to call a curl which is having a variable value as input. Using sed Command 7. Feb 1, 2017 · I am trying to add quotes to a string. Jan 6, 2020 · Without the double quotes, the variable's value would have been set to the string 123,234,456. Understanding Double Quotes in Bash What Are Double Quotes? In Bash, double quotes are special characters that encapsulate string literals. For the purposes of this question let's say I want t I'm trying to use quotes while defining an environment variable. Using awk Command 6. Apr 27, 2017 · Escaping a double quote can absolutely be necessary in sed: for instance, if you are using double quotes in the entire sed expression (as you need to do when you want to use a shell variable). Feb 5, 2024 · In Bash scripting, the dollar sign ($) holds special significance as it is used to reference the value of a variable. to write something like "foo 'bar baz' moo" or 'foo "bar baz" moo'. , the variable name. I have have string in single quotes. Quotes are used to deal with the texts, filenames with a space character. That's a single quote to end the single quoted string. Assigning command substitution doesn't require double quotes as in var=$( df ) where you have the df command's output saved to var. So what you can possibly do is rebuilding double quotes for arguments containing whitespaces This example rebuilds the whole command line, double-quoting arguments that have white Learn about Linux shell scripting and how using double quotes affects argument expansion in your scripts. If the directory name does not contain such Mar 18, 2024 · Variable interpolation happens when we use double quotes or omit quotes. example_script. Jan 5, 2023 · Quotes instruct the shell how to interpret an input string. There are four quoting mechanisms: the escape character, single quotes, double quotes, and dollar-single quotes. Avoid common pitfalls! Linux Shell Scripting. When referencing a variable, it is generally advisable to enclose its name in double quotes. Master techniques for robust scripting! Jan 23, 2024 · Escape double quotes in Bash to interpret the quotes properly within the string in a literal format and prevent errors and bugs. Importantly, the difference between these methods is that we interpret or interpolate certain combinations of characters in one context and take them literally in another. Personally, I find the style of over-quoting to be a bit excessive. Inside which I want to insert a variable and expand it. Apr 8, 2020 · Quoting strings and variable substitutions is a bit of a dark art in shell scripts. Jan 22, 2024 · 3 Examples of Quotes in Bash To clearly understand the quotes in Bash, follow the examples below and either run the commands in the terminal or create a script, put the commands, and save it. When the shell is in POSIX mode (see Bash and POSIX), the ‘! ’ has no special meaning within double quotes Jan 23, 2024 · Learning the concept of Bash single vs double quotes clearly, you can employ quotes in Bash scripts properly. Example: See Bash History Facilities, for more details concerning history expansion. Real world example of bad management of quotation in SHELL add double quotes at the beginning and end of specific variable [duplicate] Asked 7 years ago Modified 3 years, 11 months ago Viewed 32k times Dec 5, 2024 · Learn how to properly use single quotes, double quotes, and backslashes to handle special characters and variables in Bash scripts. Understanding how to handle nested quotation marks is essential for effectively manipulating strings and executing commands. e. Hint: Inside the conditional expression ([[ ]]) Bash doesn't perform word splitting, and thus you don't need to quote your variable references - they are always seen as "one word". A Jan 23, 2024 · Escape quotes are the special tools in Bash for ensuring the correct handling of single quotes, double quotes, and special characters of various forms. Now, if you want to have the latter inside a variable, just store it in a variable without any extra quotes, and use it with "$var". To put literal double-quotes in a double-quoted string -> escape them with backslashes. Though simple on the surface, proper quote handling requires understanding Bash‘s complex variable expansion rules. I'd enclose your parameters in double quotes instead of single quotes, and use either single quotes for the json keys & values or escape the double quotes in the json with \". This will work for all characters except single quote itself - i. Double quotes specify $ variables are to be substituted before execution, while single quotes specify $ are to be treated The main difference is that the quoted version is not subject to field splitting by the shell. If that means you wind up having to backslash a lot of stuff, use single quotes for most of it, and then break out of them and go into doubles for the part where you need the expansion to happen. When the shell is in POSIX mode (see Bash and POSIX), the ‘! ’ has no special meaning within double quotes Aug 5, 2023 · In the realm of bash scripting, single quotes ('') and double quotes ("") play a important role in defining how variables are treated. The braces are required when parameter is a positional parameter with more than one digit, or when parameter is followed by a character that is not to be interpreted as part of its name. You should use double quotes: Therefore, based on this experiment, it seems that, in bash, one can omit the double quotes inside [[ ]], but not inside [ ] nor in command-line arguments, whereas, in zsh, the double quotes may be omitted in all these cases. if you have a parameter containing a single quote, the output from the above command will not cut and paste correctly. Quoting is a crucial aspect of Bash scripting, allowing you to control how characters are interpreted. Feb 28, 2014 · putting multiple double quote to a bash variable seems have the same result to putting one or no double quote. There is a solution: put OPTIONS in an array, instead of a simple variable (and use double-quotes around all variable references, to keep spaces from getting treated as word separators). When the expansion occurs within double quotes, it expands to a single word with the value of each parameter separated by the first character of the IFS variable. Nov 27, 2023 · The single quotes tell bash to print the characters specified within the quotes, i. Single quotes (' ') operate similarly to double quotes, but do not permit referencing variables, since the special meaning of $ is turned off. sh echo "*. ' As you can notice that the login_token value is embedded with double quotes when passed as a variable and this causes the failure. And a single quote to start the next single quoted string. This means the $ will be treated as a literal $ character. On the other hand, double quotes interpolate the input and display the variable’s value. Without quotes it would be broken up into multiple parameters, depending on the value of IFS which contains space, TAB and newline by default. Real world example of bad management of quotation in shell scripting. bash for loop will treat a string with spaces/newlines as multiple values delimited by space. This post will explore the different types of quoting in Bash: backslashes, single quotes, and double quotes, along with their rules and usage scenarios. 44 Your shell is interpreting the quotes, both ' and ", before they even get to echo. Oct 22, 2018 · The reason to use double quotes instead of single quotes is to allow variable interpolation. I've used single quotes to ensure that other shell metacharacters are not mishandled. sh" e Dec 15, 2015 · Bash variables without double quotes can give surprising results. The methods discussed in this article use sed, tr, and parameter expansion to remove double quotes. Your last Dockerfile indeed looks like something that should be done in an entrypoint script, which can be a bash script itself. One of the simplest ways to achieve bash string interpolation is by enclosing your string within double quotes. Within single quotes, every special character except ' gets interpreted literally. Aug 9, 2009 · Double quotes behave quite differently from single quotes in *nix (including Bash, and related tools like Perl), so substituting double quotes whenever there's a problem with single quotes is NOT a good solution. [bash] #!/bin My man bash says "If the substitution appears within double quotes, word splitting and pathname expansion are not performed on the results. e. For example string="single quote: ' double quote: "'"'" end of string". Jun 20, 2021 · Please use a valid access token. For example: setenv SOME_TEMP_ENV "-arg "hello world"" Although Its fails with the following error: setenv: Too many arguments. Sep 21, 2013 · I want to print double quotes using echo statement in shell programming. Using grep Command 8. Aug 5, 2023 · In the realm of bash scripting, single quotes ('') and double quotes ("") play a important role in defining how variables are treated. Read this tutorial to understand the differences between single quote and double quotes. What is the correct way to quote my variables? And how should I do it if these are n The repo command can't care what kind of quotes it gets. when I want to define a variable,I can do as following: It's also important to note that quotes are evaluated differently; double quotes (") allow evaluation of the enclosed string, single quotes (') print the string as a literal. I know in bash variable expansion works with double quotes only. Here are some code examples ls outcome – echo variable with Mar 13, 2022 · Single quotes in bash/sh will prevent variable interpolation and result in variables beeing printed literaly. Use the double quotes when you want only variables and command substitution Variable - Yes Wildcards - No Command substitution - yes The single quote ( 'quote' ) protects everything enclosed between two single quote marks. In this article, we will explore how to manage quotation marks within a Bash script, providing both theoretical explanations and practical examples Jun 22, 2015 · In bash, how to call a variable and wrap quotes around its value as part of a command without causing the variable name to become a string literal? Ask Question Asked 10 years, 5 months ago Modified 7 years, 6 months ago 2 days ago · The root cause? **Bash’s handling of single vs. Always wrap strings and scripts in single quotes unless you need to use double quotes (e. Apr 23, 2017 · Need help in fixing this bash script to set a variable with a value including double quotes. Quote with String While working with simple texts and string, there are no different in using a single quote or double quote. Sep 12, 2021 · The shell removes the quotes, and what mycommand gets as arguments, are the two strings -f and a,b, with no quotes in them. But in the following code: #!/bin/sh echo *. Remove Double Quote from a String The sed command line utility helps to easily handle this. Take for example this right command: command -p 'cluster="cl1"' In order to automate it, I crea Apr 18, 2023 · In Bash, there are several ways to remove double quotes from a string or variable. Using quotes around a variable as in rm -- "$VAR1" or rm -- "${VAR}" is a good idea. By the end, you’ll master variable expansion in nested contexts like `ffmpeg` filters. A double quote may be quoted within double quotes by preceding it with a backslash. Feb 10, 2015 · I am a newbie to bash script programming and when I learned the variable expansion I amd puzzled by the variable. Are there any diff May 9, 2017 · I'm trying to write a bash script, and I'm running into a quoting problem. Master the nuances of bash single vs double quotes. In many languages, quotes are primarily used to denote string literals. Feb 6, 2018 · however each solution is problematic. , “$ {variable}”), the shell dynamically substitutes it with the corresponding variable’s value during script execution. That is, "$*" is equivalent to "$1c$2c…", where c is the first character of the value of the IFS variable. May 24, 2022 · Quoting when the variable is defined (or embedding quotes or escapes in the variable's value) doesn't prevent it from being word-split when it's used; you really need to double-quote when using the variable to prevent weird parsing. Then, it uses the parameter expansion to replace all occurrences for double quotes with an empty string and stores the result in updated_string. This is the reason why quotes appear in original questions examples. An unquoted, but escaped, single quote. What do nested quotes do? And when should we use quotes? Apr 26, 2025 · This tutorial will help you to remove the start and ending double quotes from strings in a shell script. You cannot nest single quotes within single quotes. The special characters inside a variable when not double quoted, gets interpreted by bash. This makes sense, but I feel like it doesn't explain why case 1 works. If you want to replace the value of a variable in a string, you can do this simply with string interpolation. The Pitfall of Unescaped Dollar Signs Consider the following script snippet: Aug 1, 2023 · (note that the is * is inside the double quotes to prevent globbing on the local host but outside the single quotes to do file globbing on the remote host) I tired it with Hint: Inside the conditional expression ([[ ]]) Bash doesn't perform word splitting, and thus you don't need to quote your variable references - they are always seen as "one word". Example: "$(ls)" and '$(ls)'. sh asd \"asd\" \'asd\' Mar 28, 2022 · If you consider that arbitrary environment variable values and names can contain newline characters (or single quotes or double quotes or non-text for that matters), it should become evident that the output of printenv cannot be post-processed reliably with line-based text utilities. Mar 18, 2024 · Learn when to use double quotes, how they work, and when to avoid them in the shell. Double quoting is not always needed, but it's easier to remember to always double quote than to memorize the contexts in which you don't need to. The thing is that the string I am searching for is also enclosed in double quotes, that is why I enclosed the whole regex in single quotes. When we need to suppress variable interpolation, we wrap the arguments in single quotes. From the Bash manual, quote removal is: After the preceding expansions, all unquoted occurrences of the characters \, ', and " that did not result from one of the above expansions are removed. Jun 5, 2012 · Execute a local bash variable inside double quotes Asked 13 years, 5 months ago Modified 13 years, 5 months ago Viewed 26k times Dec 5, 2014 · 5 I was facing the same with trying to assign a JSON string to a variable in the terminal. Jun 14, 2019 · Always double quote variable expansions, unless you explicitly want the shell to perform word-splitting and filename generation (globbing) on the strings. The json string variable must follow some special format, the double quotes must be escaped, and the whole string must be enclosed by the single quote. This approach allows Bash to evaluate any variables included within. Dec 6, 2016 · I'm trying to understand why Bash removes double quotes (but not single quotes) when doing variable expansion with ${parameter:+word} (Use Alternate Value), in a here-document, for example: This will be an easy one, but in my memories, when shell scripting, using double quotes would allow expanding globbing and variables. A space is typically the boundary character which denotes a break in atoms within a string of text for most commands. Jun 12, 2023 · As a software engineer, it’s essential to have a clear understanding of the Bash shell and its various features. Suppose, if I pass the value of login_token directly in the curl command, then the authentication is Feb 22, 2023 · You have to use double quotes (“) when expanding values by using parameter expansion. One of the most fundamental concepts in Bash scripting is the use of quotes. While seemingly similar, these two types of quotes exhibit distinct behaviors in terms of variable expansion and command substitution. Basics: why we quote strings In shell scripts (sh, bash, and zsh) you use the equals character… Quotes in Bash This is a standard practice to quote the string in any programming language. In fact, it's the user of that variable that needs to expand it within double quotes to avoid wrong splitting. The script begins with a variable declaration named main_string. Single quotes ': Preserves the literal value of all characters within the quotes, without exceptions. In this blog post, we’ll explore the differences between single and double quotes in Bash and how they affect variable expansion. Apr 12, 2019 · Key point is that without double quotes, the contents of variables are understood as separate units rather than one whole item. In this case, the primary problem is that you're trying to define OPTIONS as containing multiple words, and bash variables don't handle this very well. Therefore, it is generally a good practice to always put your shell variables inside double quotes unless you have a specific reason not to. EDIT: As some have pointed out, double-quoting does not prevent variable expansion nor command substitution. I'd like to escape single and double quotes while running a command under a different user. So, if you want to avoid escaping dollar signs and double quotes in a string and still be able to escape single quotes (for example if you are passing a complex command to a specific shell from within a bash script), then $'' is the way to go. Nov 5, 2023 · As a Linux system administrator, I frequently find myself needing to remove double quotes from strings in Bash scripts. Mar 25, 2025 · In Bash, the text is stored as strings. In the shell paradigm, many constructs are interpreted as strings by default, so quotes play other important roles. Consider the following scenario: Jun 16, 2015 · Consider I've set variable site and needs to be printed by echo or printf, but If I use single quote to write something and want to use variable then how? Example: $ site=unix. Mar 23, 2024 · Discover the importance of escaping single quotes in Bash and explore various methods, examples, and best practices to avoid syntax errors and unexpected behavior. 1. In fact, all Bash variables are just strings of characters. The way of using parameter expansion in bash has been explained in this tutorial. to let a variable expand) or need to use no quotes (e. Using tr Command 4. If you need parameter expansion, use double quotes. This is likely the closest you will get without getting messy. Variables won't be expanded in single-quoted strings. The value of login_token variable should be passed without quotes as it is. This blog dives deep into Bash quoting rules, why `$ {date}` fails in `ffmpeg` commands, and step-by-step solutions to fix it. The reason you double quote variables is because the contents of the variable may include spaces. In Bash, use double square brackets and you don't need the quotes and you get additional benefits. In this article, I’ll explain how you can employ escape quotes in Bash diversely to handle a wide range of data interpretation and create error-free scripts. com $ Jan 10, 2015 · I have an application which takes as an input attributes in double quotes embedded in single quotes. Find examples for escape characters, single and double quotes. Discover when to use each for effective command-line magic and script simplicity. Finally, the script displays the outputs indicating the main string and updated string using the echo command. Example 1: Printing Variable Output Using Quotes in Bash Follow the steps to print out the variable outputs by enclosing them within single and double quotes: Steps to Follow > Open your Ubuntu Terminal Bash Quoting Double quotes for variable and command substitution Fastest Entity Framework Extensions Bulk Insert Bulk Delete May 30, 2020 · I am trying to run a command in shell script which demands its argument to be passed in below format which includes double quotes with string. Jul 18, 2021 · You're seeing bash trying to show you that it got "*" after quote removal, so it will have to pass the double quotes on to the command. To insert variable value to interpolate a string Bash double quotes are used. if the variable in (1) or (2) contains a double quote, they will fail; if the variable in (3) contains a single quote, it will fail. Mar 11, 2022 · Learn the difference between Bash single and double quotes, and how to escape them. , t1=a, t2="a", t3=""a"", echo them prints the same result: a. Below is the snippet of a shell script from a larger script. Also, remember not to use single quotes as they can’t interpolate or insert a The basic form of parameter expansion is $ {parameter}, which substitutes the value of parameter. Where the string is stored in a variable. Without the double-quotes, the parameter expansion is subject to word splitting, and spaces will split the text into multiple arguments to curl, causing it to treat the second one as a URL Dec 5, 2020 · In short: The double quote ( "quote" ) protects everything enclosed between two double quote marks except $, ', " and \. Jun 29, 2018 · Double quotes ": Preserves the literal value of all characters within the quotes, with the exception of $, `, \ and, when history expansion is enabled, !. I‘ll […] I'm having trouble with escaping characters in bash. And to add to the confusion, my teacher told me that in order to prevent the system from misinterpreting the variable name with the text that coes after it, we should add another double quote around the variable name. 2. Nov 20, 2023 · Home > Bash > Bash String > Remove Double Quotes from String in Bash Remove Double Quotes from String in Bash Updated on November 20, 2023 by Arpit Mandliya Table of Contents [hide] 1. May 10, 2024 · The first single quote ends the single-quoted string, then there's the double-quoted variable, and the second single quote restarts the single-quoted string. Therefore if your regex contains something that can be interpreted by bash as one of those, use single quotes instead. A single-line sed command can remove quotes from the start and end Jul 26, 2023 · Using quotes can prevent this behavior and ensure that the variable is treated as a literal string. I generally just put double quotes around my argument to echo even if they're unnecessary; for example: $ echo "Hello world" Hello world So in your first example, if you want to include literal quote marks in your output, they either need to be escaped: Enclosing characters in double quotes (") preserves the literal value of all characters within the quotes, with the exception of $, ', and \ and, when history expansion is enabled, !. Nov 25, 2020 · Edit: A bunch of people have pointed out that the variables get expanded in double quotes before bash -c gets run. Bash quoting is the practice of using single quotes, double quotes, or backslashes to control how text is interpreted by the shell, allowing you to manage special characters and preserve or prevent variable expansion. Jan 17, 2014 · Variables are expanded in double quoted strings, but not in single quoted strings: Double Quotes (Bash Reference Manual)3. Oct 27, 2020 · Since I was taught to enclose variables with double-quotes. They are essential for allowing variable expansion and command substitution within strings, making it possible to dynamically change the value of strings based on the environment or user input. You can nest double quotes within double quotes by escaping them though. In this comprehensive guide, we‘ll explore the ins and outs of stripping double quotes in Bash using various built-in tools. Feb 4, 2018 · In a parameter expansion: Is it always better (or not worse) to double quote a parameter expansion than not? Are there cases where double quoting is not suggested? When is it necessary to add braces Oct 1, 2021 · Are those double quotes necessary? Based on the following test, I'd say no, and that no quote at all is needed in the above assignment. 7 Take a look at the Advanced Bash Scripting Guide, specifically section 5. Few points to note: echo will pint newline as space if variable is not quotes. If enabled, history expansion will be performed unless an ‘! ’ appearing in double quotes is escaped using a backslash. Master quotation usage in Bash scripting with practical examples. 3 Double Quotes ¶ Enclosing characters in double quotes (‘ " ’) preserves the literal value of all characters within the quotes, with the exception of ‘ $ ’, ‘ ` ’, ‘ \ ’, and, when history expansion is enabled, ‘! ’. command "string" This string is stored in variable va May 26, 2018 · In Bash, is there a way to expand variables twice in double quotes? Asked 7 years, 6 months ago Modified 5 years, 7 months ago Viewed 8k times Dec 13, 2017 · I know the question is about bash but for POSIX compatible system where the string must contain both single and double quotes you have to mix between both without spaces in between. 1 which covers quoting variables. Jan 23, 2024 · Here, in #!/bin/bash, ‘ #! ’ is called ‘ Shebang ’ or ‘ Hashbang ’. Introduction to Problem Statement 3. " (in EXPANSION > Command Substitution). double quotes** and how they interact with variable expansion. I am doing it using sed, but is it efficient? If not, then what is the See the More on variables section of the Bash Guide for Beginners and Parameter Expansion in the POSIX spec. It is critical to understand how quoting affects . touch 'some file' # create a file VAR='some file' # create a variable for that file name Dec 22, 2011 · Obviously, ${date} won't expand in single quote, please also note that there is a double quote beyond the single quote, which makes it even more complicated. Using Parameter Expansion 5. to do globbing and file name expansion). But inferring general rules from anecdotal examples like the above is a chancy proposition. The workaround is to assign a raw json string to variable, and using tools like jq to handle it during runtime. So, let’s explore! Jun 14, 2016 · They prevent field splitting on result of $( dirname "${BASH_SOURCE[0]}" ), and also the expansion of ${BASH_SOURCE[0]} (In contrast with the outer most double quotes, will are not necessary in RHS of variable assignment to prevent split+glob). If you want to pass quotes, escape them with a backslash: # . That seems to imply that we would need to quote subshell invocations. Oct 24, 2015 · NOTE: The following applies to bash, ksh, and zsh, but NOT to (mostly) strictly POSIX compliant shells such as dash; thus, when you target /bin/sh, you MUST double-quote the RHS of export. Dec 24, 2024 · When writing Bash scripts, managing quotation marks can quickly become complex, especially when dealing with nested quotes. The parameter is a shell parameter as described above (see Shell Parameters) or an array reference (see Arrays). Take a look at the Advanced Bash Scripting Guide, specifically section 5. The special parameters * and @ have special meaning when in double quotes, but you can disable them with the backslash: asked Feb 13, 2017 at 12:11 Syed Jahanzaib 145 1 1 7 Possible duplicate of Single quote within double quotes and the Bash reference manual – Chris Davies Feb 13, 2017 at 12:55 Add a comment It doesn't do a “double substitution” because there's no such feature in any of the common shells (not with this syntax anyway). I am aware that for variables to be expanded, you have to enclose the whole regex in double quotes (sed substitution with bash variables). This prevents reinterpretation of all special characters within the quoted string -- except $, ` (backquote), and \ (escape). When incorporating a variable within double quotes (e. This tutorial clarifies the difference between single and double quotes in bash. Wrap it with Single Quotes or Double Quotes Use single quotes, if you string contains double quotes and vice-versa. sh argument_without_quotes "argument with quotes i cannot escape" First consider that inside your script you can't tell if an argument is passed with or without quotes, because the shell strips them. Feb 28, 2024 · Bash supports three main types of quotations: single quotes, double quotes, and backslashes. They are usually direct, single-quoted, or double-quoted sequences. How can I escape double quotes inside a double string in Bash? For example, in my shell script Jan 24, 2021 · When you use single quotes, it causes the shell to preserve the literal value of each character within the quotes. It looks simple and straightforward enough, but there are lots of small devils in the details, that can come out and haunt you. When a string has neither variables nor whitespace, there is no reason (other than style) to use any quotes at all. Overview 2. In other words, single quotes completely protect a string from the shell while double quotes protect some things (spaces for example) but allow variables and special characters to be expanded/interpreted correctly. Thanks a lot. Oct 22, 2023 · A concise tutorial on adding or removing quotes from string bash scripts in a Linux environment. When trying to execute the bash script the variable value is not getting expanded in double quotes. like: ${list} (before appending) => ' 6 days ago · Learn about quoting difference between Bash, PowerShell, and Cmd. In my Bash environment I use variables containing spaces, and I use these variables within command substitution. You should be wondering where those double quotes came from, and I'd guess that's from your input file. Like this: stackoverflow => 'stackoverflow' And then append this string to another variable separated by a 'comma'. With double quotes the outcome of the command expansion would be fed as one parameter to the source command. Somehow I am defining this incorrectly as my values foo and bar are not enclosed in double quotes as needed. Double-quote the entire argument (as in "[abc]_[x|y]"). This makes the contents of the variable an atomic unit. Sep 21, 2025 · Learn correct quoting and variable validation in Bash to prevent bugs and enhance security. Mar 25, 2023 · Therefore, it is generally a good practice to always put your shell variables inside double quotes unless you have a specific reason not to. /script. The best you can do with single quotes is to use '\'' wherever you need an embedded single quote. g. In zsh, ${${FOO}} is valid and is a double substitution, but it behaves differently from what you'd like: it performs two successive transformations on the value of FOO, both of which are the identity Mar 18, 2024 · Variable interpolation happens when we use double quotes or omit quotes. But I'm still not able to make it work. Jul 25, 2025 · Explore bash shell quoting with single and double quotes. Quotes demarcate the arguments of a command into units called "words", as well as modify the evaluation of their contents in numerous context-dependent ways. Double Quotes (Bash Reference Manual)3. stackexchange. 1. Where exactly do you want your variables? @michaelsnowden Parameter expansion happens either in double quotes or outside of quotes completely. Feb 11, 2024 · What is String Interpolation? String interpolation refers to inserting variables, commands, and expressions into the string. Single quotes or separating characters with quotes or other characters not valid in identifiers are the only way to prevent parameter expansion. Consider single quotes ("full quoting") to be a stricter method of quoting than double quotes ("partial quoting"). Learn how to preserve literal strings, expand variables, and avoid injection vulnerabilities with practical examples. If IFS is unset, the parameters are separated by spaces. Mar 9, 2022 · Json Variable Parameter can have object type like dict in Python, but not the case for variable. Dec 29, 2022 · To expand the value of a variable within a quoted string -> use double quotes. Feb 10, 2019 · While working in a (Unix) shell, sometimes I need to double-quote single-quotes or vice versa, i. Note also that to assign a value to the variable p, no $ should precede the variable's name. vkajo usgsjrv imkjfyf ztva idpy ytqm drvl dlny xzgoqcs erl pyxb hbqxv dfq feres zcl