Applies to: Exchange Server 2007 SP3, Exchange Server
2007 SP2, Exchange Server 2007 SP1, Exchange Server 2007
Topic Last Modified: 2006-08-15
Pipelining in the Exchange Management Shell is the act of
one cmdlet using the output of another cmdlet when it performs an
operation. Pipelining is accomplished by using the pipe
"|" symbol. All verbs in the same noun-cmdlet set can
use piped information from another command. Some noun-cmdlet sets
also let you pass data through the pipeline to another noun cmdlet
set.
Using Pipelining to Perform
Multiple Actions
The use of pipelining to string together the actions of two or more cmdlets gives the Exchange Management Shell the power of composition, which lets you take smaller components and convert them into something more powerful. For example, you can use one cmdlet to gather data, pass that data to a second cmdlet to filter the data to a subset, and then pass that data to a third cmdlet to act on the subset only.
For example, the following command uses pipelining to
move all the mailboxes on Server1 to the
Executives database on Server2 by using
the Move-Mailbox cmdlet, based on output that is piped from
the Get-Mailbox cmdlet:
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Get-Mailbox -Server Server1 | Move-Mailbox -TargetDatabase Server2\Executives |
|
Using Pipelining to Process Data
from Another Cmdlet
You can also use pipelining to process data that is
output by a cmdlet. For example, for a list of all processes where
the HandleCount property of the process is larger than
400, you can run the following command:
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Get-Process | Where { $_.HandleCount -gt 400 } | Format-List
|
|
In this example, the Get-Process cmdlet passes
objects to the Where-Object cmdlet. The Where-Object
cmdlet picks out the objects that have a property called
HandleCount with a value larger than
400.
In this example, the HandleCount property
is preceded by the $_ variable. This variable is
created automatically by the Exchange Management Shell to
store the current pipeline object. The
Where-Object cmdlet then sends these
objects to the Format-List cmdlet to be
displayed.
The use of structured objects, instead of text, is one of the most exciting capabilities of the Exchange Management Shell. The use of structured objects forms the basis of a powerful compositional model of administration.
For more information about structured objects, see Structured Data.
Using Pipelining to Report
Errors
To report errors, you can use the error pipeline. The error pipeline lets you report errors while a command runs. This means that you don't have to wait until the command has finished running or to put the error information in the standard result pipeline. The Write-Error cmdlet writes its arguments to the error pipeline.
For more information about pipelining, run the following command in the Exchange Management Shell:
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Get-Help About_Pipeline |
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