Скачать или смотреть How to Store Multiple Values in a Single Variable in Linux Using Bash

Learn how to efficiently store multiple command outputs in a single variable in Linux with Bash. This detailed guide provides step-by-step instructions for both string concatenation and using an arguments array.
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This video is based on the question https://stackoverflow.com/q/63519871/ asked by the user 'Meenakshisundaram Ramanathan' ( https://stackoverflow.com/u/11984390/ ) and on the answer https://stackoverflow.com/a/63520288/ provided by the user 'Léa Gris' ( https://stackoverflow.com/u/7939871/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Store Multiple Values in a Single Variable in Linux Using Bash

When working with Bash in Linux, you might encounter situations where you need to capture multiple outputs from a loop into a single variable. For instance, you may need the output of various commands or simply want to concatenate several values without cluttering your code with multiple variables. In this post, we'll address how to store multiple command outputs into one variable and ensure they're separated by spaces as you expected.

The Challenge

Imagine you have a simple loop that iterates through a set of values, such as letters from a to e. You want to store these in a single variable called xyz. The challenge is to ensure that this variable captures all the iterations of the loop and stores them as a single string, such as:

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Solutions

There are two main ways to accomplish this in Bash: Concatenating strings directly into the variable, or using an arguments array to gather the values. Let’s explore both methods in detail.

Method 1: Concatenate Strings

This method involves appending each value to the variable xyz within the loop. Here’s how to do it step-by-step:

Step 1: Initialize the Variable

You start by initializing the variable xyz as an empty string:

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Step 2: Iterate Through Your Values

Use a for loop to go through the values you’d like to store:

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Step 3: Clean Up Extra Spaces

After the loop, you may end up with an additional leading space. To remove it, you can use string manipulation:

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Complete Script

Here’s the complete script that implements the above steps:

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Method 2: Use an Arguments Array

Another neat way to achieve the same result is by utilizing a growing arguments array. This method avoids the need for manual string manipulation to remove any leading spaces. Here’s how you do it:

Step 1: Clear Arguments Array

First, clear the arguments array using the set -- command:

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Step 2: Build the Array

In your loop, instead of concatenating to xyz, add each value to the arguments array:

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Step 3: Combine into a Single Variable

At the end of the loop, you can expand the arguments into the variable xyz:

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Complete Script

Here’s the complete script using the arguments array method:

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Conclusion

In summary, whether you use string concatenation or utilize an arguments array, both methods effectively allow you to store multiple values in a single variable in Linux. Experiment with both techniques to find which one you prefer or which suits your specific scripting needs better. With this knowledge, you're now better equipped to manage variable outputs in your Bash scripts efficiently!