Powershell to start/stop with arg - powershell

Question

I've written the following function in test.ps1 and I would like to make a choise when running thsi script to start/stop/.. :
function getState($SeviceName) {
$server = #('host_1', 'host_2')
# get status
$server | % {Write-Host "verify: $_"; Get-Service -ComputerName $_ -Name SeviceName
}
I would like to provide $ServiceName as argument (with stdin) how can I do it? => somthing like choose 1 to start 2 to stop ...
To use switch/case in Powershell
$doAction = {"Stop-Service", "Start-service"}
$server | % {Write-Host "verify: $_"; Get-Service -ComputerName $_ -Name SeviceName | $doAction}
How do I use the switch to select start or stop?

Answer 1

Here's a function that will do what you're asking for:
function Get-State {
[CmdletBinding()]
[OutputType('System.ServiceProcess.ServiceController')]
param(
[Parameter(Position = 0, Mandatory)]
[ValidateSet('Start', 'Stop', 'Get')]
[string] $Action,
[Parameter(Position = 1, ValueFromPipeline, Mandatory)]
[ValidateNotNullOrEmpty()]
[string] $ServiceName
)
begin {
$serverList = #('host_1', 'host_2')
}
process {
foreach ($server in $serverList) {
try {
$svc = Get-Service -ComputerName $server -Name $ServiceName -ErrorAction Stop
} catch {
throw "Failed to find service $ServiceName on $server! $PSItem"
}
switch ($Action) {
'Start' { $svc | Start-Service -PassThru }
'Stop' { $svc | Stop-Service -Force -PassThru }
default { $svc }
}
}
}
}
It utilizes advanced function features and attributes to take pipeline input (stdin in your words). I'd suggest reading this documentation.

Answer 2

You can add argument to a script by adding parameters to it.
On the top of your script file put:
Param
(
[parameter()]
[String[]]$YourArgumentVariable
[parameter()]
[switch] $MySwitch
)
With a function it goes right after the function definition. So in your case:
function getState($SeviceName) {
Param
(
[parameter()]
[String[]]$server
[parameter()]
[switch] $MySwitch
)
# get status
$server | % {Write-Host "verify: $_"; Get-Service -ComputerName $_ -Name SeviceName
}
A switch basically sets a boolean to true or false.
So in this if you call the script with -MySwitch it will set the variable $MySwitch to true. Else it will remain false.
Don Jones has written a good getting started article on paramters that I would recommend you checking out.
Do note that there are loads of things you can define in the paramter. Like if you want to make sure it is always filled you can set
[parameter(Mandatory=$true)]
This is just one of many examples of what you can do with paramters.