The JavaScript String substring() function is used to extract a portion of a string and return it as a new string. It takes two parameters: the starting index and the ending index of the substring. The starting index is inclusive, meaning the character at that index is included in the substring, while the ending index is exclusive, meaning the character at that index is not included in the substring. If the ending index is not specified, the substring will include all characters from the starting index to the end of the string. If the starting index is greater than the ending index, the substring function will swap the two values before extracting the substring. Keep reading below to learn how to Javascript String substring in Bash.

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Javascript String substring in Bash With Example Code

JavaScript’s `substring()` method is a useful tool for manipulating strings. But what if you need to use it in a Bash script? Fortunately, there is a way to achieve this using parameter expansion.

Parameter expansion is a feature in Bash that allows you to manipulate variables in various ways. One of these ways is by using the `${variable:offset:length}` syntax, which is similar to the `substring()` method in JavaScript.

To use this syntax, you need to first assign the string to a variable in your Bash script. For example:

myString="Hello, world!"

To extract a substring from this string, you can use the `${variable:offset:length}` syntax. The `offset` parameter specifies the starting position of the substring, and the `length` parameter specifies the number of characters to extract. For example, to extract the substring “world” from the string above, you can use:


This will assign the value “world” to the `mySubstring` variable.

You can also use this syntax to extract substrings from command output. For example, to extract the first 10 characters of the output of the `ls` command, you can use:



This will assign the first 10 characters of the output of the `ls` command to the `mySubstring` variable.

In conclusion, using parameter expansion in Bash allows you to achieve similar functionality to the `substring()` method in JavaScript. By using the `${variable:offset:length}` syntax, you can extract substrings from strings and command output in your Bash scripts.

Equivalent of Javascript String substring in Bash

In conclusion, the Bash shell provides a powerful set of string manipulation tools that can be used to perform a wide range of tasks. One of these tools is the substring function, which allows you to extract a portion of a string based on its position and length. While the syntax and functionality of the Bash substring function may differ from its equivalent in JavaScript, it is nonetheless a valuable tool for anyone working with strings in a Unix or Linux environment. By mastering the substring function and other string manipulation tools in Bash, you can streamline your workflow and become a more efficient and effective developer.

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