Introduction

Bash, born out of the Unix shell tradition, is a valuable asset as the glue that orchestrates the execution of a set of computer programs. As a versatile command-line interpreter, Bash excels in automating repetitive tasks, stringing together disparate programs, and facilitating the flow of data between them. These abilities make Bash a particularly interesting option to implement computer pipelines or workflows, which typically combine programs written in different programming languages.

When implementing pipelines, it is necessary to consider not only standard software engineering principles such as modularity or code reusability, but also specific challenges inherent to pipeline design. One example of these challenges is the optimal use of hardware resources. A pipeline involves the execution of a series of steps where parallelism can be exploited depending on the data dependencies between such steps. This observation has motivated a growing interest in the application of data flow programming paradigms as opposed to the traditional control flow approach.

In spite of the fact that Bash incorporates features useful to enable parallel process execution, it is still focused on the sequence of operations to be executed and the flow of control between the differents parts of a program. This makes the application of Bash difficult in scenarios where data flow programming is more appropriate.

DeBasher is a flow-based programming extension for Bash that allows to implement general programs escaping the traditional control flow paradigm. Flow-based programming combines data flow programming with component-based software engineering, resulting in programs that naturally exploit process parallelism and at the same time optimize modularity and code reuse.

In spite of the fact that DeBasher uses Bash as native language, it should be highlighted that flow-based programming is by nature language agnostic. Because of that, DeBasher allows the user to implement the program components in multiple programming languages and not only Bash.