How to handle command-line arguments in PowerShell - powershell

Question

What is the "best" way to handle command-line arguments?
It seems like there are several answers on what the "best" way is and as a result I am stuck on how to handle something as simple as:
script.ps1 /n name /d domain
AND
script.ps1 /d domain /n name.
Is there a plugin that can handle this better? I know I am reinventing the wheel here.
Obviously what I have already isn't pretty and surely isn't the "best", but it works.. and it is UGLY.
for ( $i = 0; $i -lt $args.count; $i++ ) {
if ($args[ $i ] -eq "/n"){ $strName=$args[ $i+1 ]}
if ($args[ $i ] -eq "-n"){ $strName=$args[ $i+1 ]}
if ($args[ $i ] -eq "/d"){ $strDomain=$args[ $i+1 ]}
if ($args[ $i ] -eq "-d"){ $strDomain=$args[ $i+1 ]}
}
Write-Host $strName
Write-Host $strDomain

Answer 1

You are reinventing the wheel. Normal PowerShell scripts have parameters starting with -, like script.ps1 -server http://devserver
Then you handle them in a param section (note that this must begin at the first non-commented line in your script).
You can also assign default values to your params, read them from console if not available or stop script execution:
param (
[string]$server = "http://defaultserver",
[Parameter(Mandatory=$true)][string]$username,
[string]$password = $( Read-Host "Input password, please" )
)
Inside the script you can simply
write-output $server
since all parameters become variables available in script scope.
In this example, the $server gets a default value if the script is called without it, script stops if you omit the -username parameter and asks for terminal input if -password is omitted.
Update:
You might also want to pass a "flag" (a boolean true/false parameter) to a PowerShell script. For instance, your script may accept a "force" where the script runs in a more careful mode when force is not used.
The keyword for that is [switch] parameter type:
param (
[string]$server = "http://defaultserver",
[string]$password = $( Read-Host "Input password, please" ),
[switch]$force = $false
)
Inside the script then you would work with it like this:
if ($force) {
//deletes a file or does something "bad"
}
Now, when calling the script you'd set the switch/flag parameter like this:
.\yourscript.ps1 -server "http://otherserver" -force
If you explicitly want to state that the flag is not set, there is a special syntax for that
.\yourscript.ps1 -server "http://otherserver" -force:$false
Links to relevant Microsoft documentation (for PowerShell 5.0; tho versions 3.0 and 4.0 are also available at the links):
about_Scripts
about_Functions
about_Functions_Advanced_Parameters