The concept of pipelines originated in Unix-like operating systems, with the introduction of the Thompson shell (sh) in the early 1970s. In Bash, the default shell for many Unix-based systems, pipelines allow commands to be chained together, with the output of one command serving as the input for the next. This revolutionized command-line interactions, enabling powerful text-based data processing.
However, Bash pipelines were limited to processing text output. While this was sufficient for many tasks, it posed challenges when dealing with structured or complex data. Enter PowerShell.
PowerShell, Microsoft's powerful command-line shell and scripting language, took pipelines to the next level with the introduction of object-oriented pipelines. Unlike Bash, which dealt primarily with text output, PowerShell cmdlets output .NET objects, providing a more structured and versatile data processing environment.
With PowerShell, objects flow through the pipeline, allowing for seamless manipulation of properties and methods. This object-oriented approach opens up a world of possibilities, enabling developers to work with complex data structures effortlessly.
One of PowerShell's standout features is its support for passing objects through the pipeline by value or by property name. The ByValue option allows entire objects to be passed between commands, preserving their integrity and enabling rich data transformations. On the other hand, the ByPropertyName option allows specific properties of objects to be passed along the pipeline, providing fine-grained control over data processing.
This flexibility empowers users to craft elegant and efficient pipelines tailored to their specific needs, whether it's performing complex data transformations or automating system administration tasks.
Another beauty is many commandlet's ability to handle arrays as input. I became used to taking arrays, running them through a foreach or foreach-object loop and manipulating them that way. It became my go-to. What really blew my mind was learning that many of these commandlets accept arrays as an input and will handle the "looping" for you. For example if you have an array of services that you've whittled down with where-objects etc and you need to stop them all, you could either pipe them to foreach-object and stop each individual service
$services | foreach-object{
stop-service $_.name
}
Or you can just pipe the service objects to the command stop-service, which accepts an array of objects as its input!
$services | stop-service
Honestly, sometimes it ends up creating embarrassingly short and simple looking scripts. Its then I remind myself that this beautifully simple solution is not embarrassing, but elegant.
From its humble origins in Bash to its evolution in PowerShell, pipelines have remained a cornerstone of command-line interfaces, enabling efficient and elegant data processing workflows. While Bash laid the groundwork with its text-based pipelines, PowerShell's introduction of object-oriented pipelines has elevated the art of data manipulation to new heights.
By embracing the beauty of pipelines, developers can unlock the full potential of their command-line interactions, streamlining tasks and unleashing creativity in data processing. Whether you're a seasoned sysadmin or a budding developer, mastering the art of pipelining is sure to enhance your command-line prowess.