How to Set Command Line Args with Space Delimited Contents in Zsh

Learn how to easily parse and set command line arguments in `Zsh` from a space-delimited argument string.
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How to Set Command Line Args with Space Delimited Contents in Zsh

When working with shell scripting in Zsh, you might encounter a situation where you receive a command line argument that contains a space-delimited list of other arguments. The challenge then becomes how to effectively set these individual arguments within your script for further processing. In this guide, we will tackle this problem head-on and demonstrate a straightforward solution using the set command.

Understanding the Problem

Suppose you have a script that receives a single string input, which is, in fact, a list of arguments separated by spaces. For example, when invoking your script, you pass the following command:

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Here, "$1" will capture the entire string "-a -b -c", which you would like to split into separate arguments -a, -b, and -c. This is important because you may want to use these arguments in your script for further processing, such as passing them to functions or commands.

The Solution

The solution to splitting the space-delimited arguments can be achieved with a simple command in Zsh. We'll utilize the set command along with parameter expansion to handle the splitting.

Step-by-Step Guide

Script Setup: Create a new script file. For instance, let's call it script.zsh.

Using the Set Command: Inside your script, you'll use the following line to split the arguments:

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Here’s what this line does:

set -- is a command that sets the positional parameters of the script.

"${(z)1}" splits the first argument $1 into separate words based on spaces.

Iterate Over Arguments: Once you've set the positional parameters, you can iterate through them using a for loop.

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Each argument will be available separately as $arg.

Example Implementation

Here’s the complete code for your script.zsh:

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Running the Script

Now, execute your script with the command line arguments. Here's an example:

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Expected Output

The output will be:

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This clearly shows that each argument has been successfully separated and can be processed individually.

Advanced Usage: Removing Quotes

If your arguments might come with additional quotes that you wish to strip away, you can modify the command slightly:

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This command removes an additional level of quotes when splitting the arguments, which might be helpful in certain scenarios.

Conclusion

Using set -- "${(z)1}" in Zsh provides a powerful way to handle space-delimited command line arguments. This method ensures that you can effectively manage and use each individual argument in your script, simplifying your workflow and enhancing your scripting efficiency. So next time you’re faced with a complex command line input, remember this approach to turn it into manageable pieces.

With these steps, you'll be well-equipped to handle space-delimited command line arguments in your Zsh scripts like a pro!