Is PowerShell ready to replace my Cygwin shell on

Question

I'm debating whether I should learn PowerShell, or just stick with Cygwin/Perl scripts/Unix shell scripts, etc.

The benefit of PowerShell would be that the scripts could be more easily used by teammates that don't have Cygwin; however, I don't know if I'd really be writing that many general purpose scripts, or if people would even use them.

Unix scripting is so powerful, does PowerShell come close enough to warrant switching over?

Here are some of the specific things (or equivalents) I would be looking for in PowerShell:

• grep
• sort
• uniq
• Perl (how close does PowerShell come to Perl's capabilities?)
• AWK
• sed
• file (the command that gives file information)
• etc.

Answer 1

I have only recently started dabbling in PowerShell with any degree of seriousness. Although for the past seven years I've worked in an almost exclusively Windows-based environment, I come from a Unix background and find myself constantly trying to "Unix-fy" my interaction experience on Windows. It's frustrating to say the least.

It's only fair to compare PowerShell to something like Bash, tcsh, or zsh since utilities like grep, sed, awk, find, etc. are not, strictly speaking, part of the shell; they will always, however, be part of any Unix environment. That said, a PowerShell command like Select-String has a very similar function to grep and is bundled as a core module in PowerShell ... so the lines can be a little blurred.

I think the key thing is culture, and the fact that the respective tool-sets will embody their respective cultures:

• Unix is a file-based, (in general, non Unicode) text-based culture. Configuration files are almost exclusively text files. Windows, on the other hand has always been far more structured in respect of configuration formats--configurations are generally kept in proprietary databases (e.g., the Windows registry) which require specialised tools for their management.

• The Unix administrative (and, for many years, development) interface has traditionally been the command line and the virtual terminal. Windows started off as a GUI and administrative functions have only recently started moving away from being exclusively GUI-based. We can expect the Unix experience on the command line to be a richer, more mature one given the significant lead it has on PowerShell, and my experience matches this. On this, in my experience:

  • The Unix administrative experience is geared towards making things easy to do in a minimal amount of key strokes; this is probably as a result of the historical situation of having to administer a server over a slow 9600 baud dial-up connection. Now PowerShell does have aliases which go a long way to getting around the rather verbose Verb-Noun standard, but getting to know those aliases is a bit of a pain (anyone know of something better than: alias | where {$_.ResolvedCommandName -eq "<command>"}?).

    An example of the rich way in which history can be manipulated:

    iptables commands are often long-winded and repeating them with slight differences would be a pain if it weren't for just one of many neat features of history manipulation built into Bash, so inserting an iptables rule like the following:

    iptables -I camera-1-internet -s 192.168.0.50 -m state --state NEW -j ACCEPT

    a second time for another camera ("camera-2"), is just a case of issuing:

    !!:s/-1-/-2-/:s/50/51

    which means "perform the previous command, but substitute -1- with -2- and 50 with 51.

  • The Unix experience is optimised for touch-typists; one can pretty much do everything without leaving the "home" position. For example, in Bash, using the Emacs key bindings (yes, Bash also supports vi bindings), cycling through the history is done using Ctrl-P and Ctrl-N whilst moving to the start and end of a line is done using Ctrl-A and Ctrl-E respectively ... and it definitely doesn't end there. Try even the simplest of navigation in the PowerShell console without moving from the home position and you're in trouble.

  • Simple things like versatile paging (a la less) on Unix don't seem to be available out-of-the-box in PowerShell which is a little frustrating, and a rich editor experience doesn't exist either. Of course, one can always download third-party tools that will fill those gaps, but it sure would be nice if these things were just "there" like they are on pretty much any flavour of Unix.

• The Windows culture, at least in terms of system API's is largely driven by the supporting frameworks, viz., COM and .NET, both of-which are highly structured and object-based. On the other hand, access to Unix APIs has traditionally been through a file interface (/dev and /proc) or (non-object-oriented) C-style library calls. It's no surprise then that the scripting experiences match their respective OS paradigms. PowerShell is by nature structured (everything is an object) and Bash-and-friends file-based. The structured API which is at the disposal of a PowerShell programmer is vast (essentially matching the vastness of the existing set of standard COM and .NET interfaces).

In short, although the scripting capabilities of PowerShell are arguably more powerful than Bash (especially when you consider the availability of the .NET BCL), the interactive experience is significantly weaker, particularly if you're coming at it from an entirely keyboard-driven, console-based perspective (as many Unix-heads are).

Answer 2

When you compare PowerShell to the combination Cygwin/Perl/Shell, be aware that PowerShell only represents the "Shell" part of that combination.

You can however invoke any command from PowerShell just as you do from cmd.exe or Cygwin. It does not re-implement the specified functions, and it is certainly not comparable to Perl.

It's "just" a shell, but it makes programming easier providing a comfortable interface to the .Net universe.

Also keep in mind that PowerShell requires WinXP, Srv2003 or higher, which may pose a problem depending on your IT infrastructure.

Update:

I had no idea what kind of philosophical debate my answer would spark.

I posted my answer in the context of the question: Compare PowerShell to Cygwin and Perl and bash.

PowerShell is a shell, as it makes no syntactic difference between built-in commands, commandlets, user functions, and external commands (.exe, .bat, .cmd). Only invoking .Net methods differ by adding a namespace or an object in the call.

Its programmability derives from .Net framework, not from anything specific to the PowerShell "language".

I'd say I believe PowerShell is a "scripting language" as soon as Bugzilla or MediaWiki are implemented as PowerShell scripts running on a web server ;)

Until then, enjoy the comparisons.

Answer 3

If you like shell scripting you will love PowerShell!

Start at A guided tour of the Microsoft Command Shell (Ars Technica).

Answer 4

You can also try running Bash scripts on Windows using BashWin at https://github.com/skanga/BashWin.

Answer 5

I found PowerShell programming to be not worth the effort.

I have several years of experience with shell scripting under Unix, but I found it enormously difficult to do much of anything with PowerShell.

It seems like many functions require you to interrogate the Windows Management Interface and issue SQL-like commands to get the information you need.

For example, I wanted to write a script to remove all files with a specific suffix from a directory tree. Under Unix, this would be a simple ...

find . -name \*.xyz -exec rm {} \;

After a couple of hours dicking around with Scripting.FileSystemObject and WScript.Shell and issuing "SELECT * FROM Win32_ShortcutFile WHERE Drive = '" & drive & "' AND Path = '" & searchFolder & "'", I finally gave up and settled for Windows Explorer's Search command and just do it manually. There's probably some way to do what I wanted, but I didn't see anything obvious and all the examples on the MSDN site were so trivial as to be worthless.

EDIT Heh, of course as soon as I wrote this I poked around some more and found what I had been missing: the -recurse option to the remove-item command is faulty (revealed if you use get-help remove-item -detailed).

I had been trying "remove-item -filter '* .xyz' -recurse" and it wasn't working, so I gave up on it.

Turns out you need to use get-childitem -filter '*.xyz' -recurse | remove-item

Answer 6

The cmdlets in PowerShell are very nice and work reliably. Their object-orientedness appeals to me a lot since I'm a Java/C# developer, but it's not at all a complete set. Since it's object oriented, it's missed out on a lot of the text stream maturity of the POSIX tool set (awk and sed to name a few).

The best answer I've found to the dilemma of loving OO techniques and loving the maturity in the POSIX tools is to use both! One great aspect of PowerShell is that it does an excellent job piping objects to standard streams. PowerShell by default uses an object pipeline to transport its objects around. These aren't the standard streams (standard out, standard error, and standard in). When PowerShell needs to pass output to a standard process that doesn't have an object pipeline, it first converts the objects to a text stream. Since it does this so well, PowerShell makes an excellent place to host POSIX tools!

The best POSIX tool set is GnuWin32. It does take more than 5 seconds to install, but it's worth the trouble, and as far as I can tell, it doesn't modify your system (registry, c:\windows\* folders, etc.) except copying files to the directories you specify. This is extra nice because if you put the tools in a shared directory, many people can access them concurrently.

GnuWin32 Installation Instructions

Download and execute the exe (it's from the SourceForge site) pointing it to a suitable directory (I'll be using C:\bin). It will create a GetGnuWin32 directory there in which you will run download.bat, then install.bat (without parameters), after which, there will be a C:\bin\GetGnuWin32\gnuwin32\bin directory that is the most useful folder that has ever existed on a Windows machine. Add that directory to your path, and you're ready to go.