Wednesday, July 12, 2006
> gcm out-*Out-Default cmdlet is one of the most mysterious one.
CommandType Name Definition
----------- ---- ----------
Cmdlet Out-Default Out-Default [-InputObject <P...
Cmdlet Out-File Out-File [-FilePath] <String...
Cmdlet Out-Host Out-Host [-Paging] [-InputOb...
Cmdlet Out-Null Out-Null [-InputObject <PSOb...
Cmdlet Out-Printer Out-Printer [[-Name] <String...
Cmdlet Out-String Out-String [-Stream] [-Width...
> help out-defaultThe help message does not help at all. Luckily enough, Jeffrey Snover has a blog entry talking about this cmdlet. In summary, It will "figure out how to format and output the object stream" and send them to host via Out-host cmdlet.
The default controller of output.
The standard treatment at the end of a pipeline is to send all objects to o
ut-default. Out-default then sends them all to format-default. It takes th
e objects that return and sends them to the default destination. For this
reason, it is functionally equivalent to out-host but is not called from th
Here is my two cents:
1. Out-Default cmdlet is NOT for interactive console User.
Every interactive command from console will have Out-Default appended automatically by Monad engine. Add Out-Default in the middle of pipline could even cause unexpected output.
> gps | format-table2. Out-Default cmdlet is for Monad hosting application.
> gps | out-default | format-table # format-table will not work.
To have a full-blown Monad hosting application, you have to create your own "Host" (System.Management.Automation.Host.PSHost) which implement interface to process output (If you don't have your PSHost output interface implemented, your will get an exception when Out-default finally called out-host.). Every interactive command from user input should have Out-Default appended. Then the output of user command were assessed by out-default, formatted by format-* cmdlet, and eventually sent to user interface by out-host cmdlet.
using System.Management.Automation;Although you don't have to (and probably should not) type "Out-Default" at the end of your command, it is always there working for you. Given this reason, Out-Default cmdlet is registered and loaded as default cmdlets.
static void Main(string args)
string command = "gps";
PSHost myhost = new MyHost();
Runspace myRunspace = RunspaceFactory.CreateRunspace(myhost);
Pipeline pipeline1 = myRunspace.CreatePipeline(command, true);
Class MyHost : PSHost
// MyHost class should be derived from PSHost abstract class.
You see it is there, you do not use it, but it is definitely important.
Jeffrey Snover [MSFT]
Windows PowerShell/Aspen Architect
Visit the Windows PowerShell Team blog at: http://blogs.msdn.com/PowerShell
Visit the Windows PowerShell ScriptCenter at: http://www.microsoft.com/technet/scriptcenter/hubs/msh.mspx
and i find that even with out-default, objects don't always come back in a way that is easily converted to text.
Oes Tsetnoc | Semangat Mengembalikan Jati Diri Bangsa
Links to this post: