PowerShell Grows Up

I am excited about the emminent release of Microsoft Windows Powershell Version 2 CTP3 (Community Technology Preview Version 3) which is due "real soon now."   The first CTP for Powershell 2.0 was in November 2007 and there has been a lot of progress on the product since then.  See the permanant link at the side of my blog to access the Powershell developers blog.

Why am I, a UNIX/Linux developer, excited by Powershell V2?  After all it does not run on any UNIX or GNU Linux platform and microsoft has no plans to port itMto these platforms.  The main reason is that Powershell V2 supports non-compiled functions (known as script cmdlets) in scripts just like bash or ksh93 does while providing deep object orientated interfaces to the operating system and underlying platform.  Previously cmdlets had to be written in a compiled language such as C# or VB.NET in order to provide such functionality.  (Currently, the terminology for what is generally know as a function in a UNIX/GNU Linux shell script is called a script cmdlet in Powershell but this is apparantly on track to change to function in CTP3.)  Another reason is the introduction of a graphic interface to Powershell.

I have spend more than 25 years of my life working on or with UNIX, UNIX-like or GNU/Linux operating systems.  For a period of that time, I was responsible for maintenance and enhancement of various shells and hence still maintain an interest in this area.  Much progress has occured in UNIX/GNU Linux shells over that period of time with bash, zsh and ksh93 emerging as the de facto leaders and csh, tcsh, sh (as in the Steve Bourne shell) and ash slowly fading away into obscurity.  

Standardization of functionality for portable shell scripts has moved from simply "use the Bourne shell if you want your script to run everywhere" to written specifications such as POSIX which all three shells support.  Numerious attempts (dtksh, Wksh, tksh come to mind) have been made to develop shells with graphical interfaces but none has been really successful.  Currently work is afoot to provide deeper interfaces into the operating system and platform with the latest versions of ksh93 having support for compiled builtins, compound variables and quasi-objects (which I plan to write about soon in another post.)

While it may be tantamount to heresy to say this, but kudos to the Microsoft Powershell development team who have managed in my opinion to leapfrog all the UNIX//GNU Linux shells in terms of functionality with Powershell V2.  I think UNIX/GNU Linux shell developers could learn a lot from taking a hard look at its design and functionality.


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