The secret of success with Invoke-Command is to pay particular attention to these
three parameters:
-ComputerName to make that remote connection, (-Computer is
unambiguous and works just as well).
-ScriptBlock place the payload of your command is
inside the {Braces}.
-FilePath store the PowerShell instructions in
a file, then run against multiple machines.
Get-Help When investigating the scope and parameters
for any new command, I call for Get-Help followed by the name of the cmdlet,
this is how I learned about the above parameters.
{"C:\Program files" | GCI or Get-ChildItem} is just for illustration, a more common usage
would be PowerShell cmdlets such as Get-Service or Get-Eventlog.
# Invoke-Command -ScriptBlock example in PowerShell 2.0 Invoke-Command -ComputerName
BigServer, LittleServer ` -ScriptBlock {Get-Process | Where-Object
{$_.name -Like 'W*'}}
Note 1: The backtick ` tells PowerShell to word-wrap
to the second line.
Note 2: You could also store a list of
computer names in a file and call the file with: Invoke-Command
-ComputerName (Get-Content "E:\PowerShell\com\ServerList.txt")
Note 3: If the ScriptBlock does not do what you
want, and you wish to append string commands, try
Invoke-Expression
instead.
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Using the -FilePath parameter is an alternative technique to
employing -ScriptBlock. The idea is that you store all the
PowerShell instructions in a .ps1 file. Then instead of looking
for a ScriptBlock, you point Invoke-Command at the -FilePath. The
benefit is that you don't have to keep a copy of the file on all the
remote servers for which you want to run the script.
Jobs and -asJob For scripts that take a long time to complete you could consider
appending the -asJob
parameter. This has the pleasant effect of running the commands in the
background. However, to actually see the results, you need to master the cmdlet
receive-Job.
As an alternative to -asJob you could be to employ the -session parameter
then run Start-job. However from a learning perspective, I normally
like to concentrate on one technique at a time and combining Invoke-Command
with start-Job is a tricky task for a beginner.
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Invoke-Expression is a sister PowerShell cmdlet useful for mimicking the CMD dos box. A
typical
scenario is where you can typing command-line
instructions, but now you want to execute the same string using
PowerShell.
With Invoke-Expression you can either save the string values in a text
file, then execute them, else append the string directly to
Invoke-Expression. See
more about Invoke-Expression here.
Here is handy remoting technique for running PowerShell commands on a batch
of network machines. Learn more about the syntax and parameters with help
Invoke-Command, the key to this cmdlet is what you put between the -ScriptBlock
{Braces}.
If you like this page then please share it with your friends
Please email me if you have a better example script. Also please report any factual mistakes, grammatical errors or broken links, I will be happy to correct the fault.
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