Source multiple files in background/parallel (ZSH)

When working with the ZSH shell, you may often need to source multiple files at once. Sourcing a file means executing its contents in the current shell session, which can be useful for defining variables, functions, and aliases. By default, ZSH sources files sequentially, meaning it waits for each file to finish sourcing before moving on to the next one. However, you can also source files in the background or in parallel, which can significantly speed up the process, especially when dealing with large or slow files.

Background Sourcing

Background sourcing allows you to source files without waiting for them to finish before moving on to the next command. This can be particularly useful when you have files that take a long time to source or when you want to continue working while the files are being sourced in the background.

To source a file in the background, you can use the source command followed by the file name, and then append an ampersand (&) at the end. For example:

This will start sourcing file1.zsh in the background, allowing you to continue using the shell immediately.

If you want to source multiple files in the background, you can simply chain the commands using the ampersand symbol. For example:

This will start sourcing all three files simultaneously in the background.

Parallel Sourcing

Parallel sourcing takes background sourcing to the next level by allowing you to source multiple files at the same time using parallel processes. This can be especially useful when you have a large number of files to source, as it can significantly reduce the overall sourcing time.

To source files in parallel, you can use the parallel-source plugin for ZSH. First, you need to install the plugin. If you are using a package manager like Homebrew on macOS, you can run the following command:

If you are using a different package manager or operating system, please refer to the plugin's documentation for installation instructions.

Once the plugin is installed, you can source files in parallel by using the parallel_source command followed by the file names. For example:

This will start sourcing all three files in parallel, using separate processes for each file. The plugin takes care of managing the parallel execution and ensures that the files are sourced correctly.

It's important to note that parallel sourcing may not always result in faster execution, especially if the files are small or if your system has limited resources. In some cases, the overhead of managing multiple processes can outweigh the benefits of parallel execution. Therefore, it's recommended to test and benchmark your specific use case to determine if parallel sourcing is beneficial.

Conclusion

Sourcing multiple files in the background or in parallel can greatly improve your productivity when working with the ZSH shell. Background sourcing allows you to continue working while files are being sourced, while parallel sourcing can significantly reduce the overall sourcing time, especially for a large number of files. By using these techniques, you can streamline your workflow and make the most out of your ZSH shell.

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