CODEWITHSUNDEEP
powershellparametersargumentsparameter-passingoptional-parameters
Jesko Hüttenhain
Jesko Hüttenhain

Reputation: 1307

Consume $args while also using parameter set names

Consider the following toy example script test.ps1:

Param(
    [Parameter(ParameterSetName='readfile',Position=0,Mandatory=$True)]
    [string] $FileName,

    [Parameter(ParameterSetName='arg_pass',Mandatory=$True)]
    [switch] $Ping
)

if ($Ping.isPresent) {
    &$env:ComSpec /c ping $args
} else {
    Get-Content $FileName 
}

The desired effect would be that

.\test.ps1 FILE.TXT

displays the contents of FILE.TXT and

.\test.ps1 -Ping -n 5 127.0.0.1

pings localhost 5 times.

Unfortunately, the latter fails with the error

A parameter cannot be found that matches parameter name 'n'.
At line:1 char:18
+ .\test.ps1 -Ping -n 5 127.0.0.1
+                  ~~
    + CategoryInfo          : InvalidArgument: (:) [test.ps1], ParameterBindingException
    + FullyQualifiedErrorId : NamedParameterNotFound,test.ps1

This is just a minimal example, of course.

In general, I am looking for a way to introduce a [switch] parameter to my script that lives inside its own parameter set and when that switch is present, I want to consume all remaining arguments from the commandline and pass them on to another commandline application. What would be the way to do this in PowerShell?

Upvotes: 1

Views: 252

Answers (1)

Bill_Stewart
Bill_Stewart

Reputation: 24585

You can use the ValueFromRemainingArguments parameter attribute. I would also recommend specifying a default parameter set name in CmdletBinding. Example:

[CmdletBinding(DefaultParameterSetName="readfile")]
param(
  [parameter(ParameterSetName="readfile",Position=0,Mandatory=$true)]
    [String] $FileName,
  [parameter(ParameterSetName="arg_pass",Mandatory=$true)]
    [Switch] $Ping,
  [parameter(ParameterSetName="arg_pass",ValueFromRemainingArguments=$true)]
    $RemainingArgs
)
if ( $Ping ) {
  ping $RemainingArgs
}
else {
  Get-Content $FileName 
}

(Aside: I don't see a need for & $env:ComSpec /c. You can run commands in PowerShell without spawning a copy of cmd.exe.)

Upvotes: 4

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