Directory contents as an option

[IceboxDev]

Implementing the ability to use the contents of a directory as a valid option in GRML is essential for enhancing its usability and efficiency. Currently, users must often specify singular files within a directory for testing purposes, which is both time-consuming and prone to error, especially when dealing with large variance or frequently updated datasets.

Folder:

Grml functionality:

[IceboxDev]

The most beautiful solution would be one where the folder options can either be single-choice (As implemented in #14) or multiple-choice:

but unclear how the syntax for the differentiation should look like...