When you want to find out how things are working in PowerShell, the first command to check is the get-help command. The help cmdlet can be used in various ways:
help <command>
man <command>
<command> -?
help about*
and there are a few more ways to achieve the same thing.
You can ask PowerShell to view different sections of the help by adding some switches like -detailed, -full or even
-examples to get the examples section of the command.
There is also the parameters section that lists all parameters a cmdlet supports. To list
all accepted parameters, type:
get-help <command> -parameter *
PowerShell also supports a shortened notation of parameters. If a cmdlet has a parameter
named -include, then you can type -i as long as there is no additional parameter
that starts with "i". In the case of multiple parameters that start with the
same characters, you need to distinguish the parameter by adding another character, something like:
Select-String -inc # -include
Select-String -inp # -inputObject
Most of the time typing get-help to discover parameters results in a few help pages,
and navigating them to find what you need can be a very long process, not to mention how your console looks like
when you want to see the last commands you have typed.
Another issue is commands written with abbreviated parameters. something like:
Set-Content -l "argument" -pas "argument" -fi "argument" -l "argument" -fo
which you need to decipher by yourself. Although you can guess the parameter objective
by its argument, it can be quite a deciphering process.
This is where this utility function comes in hand. I wrote it as a learning tool for parameters.
It will print out three columns for the given cmdlet (you can add more):
1. parameter name
2. Alias, new column which calculates the distinguished part of the parameter.
3. positioned column
So, to get all params for select-string cmdlet
PS C:\Scripts>get-params select-string
-----------------
- select-string -
-----------------
name alias position Type
---- ----- -------- ----
caseSensitive -c named SwitchParameter
exclude -e named string[]
include -inc named string[]
inputObject -inp named psobject
list -l named SwitchParameter
path -path 2 string[]
pattern -patt 1 string[]
quiet -q named SwitchParameter
simpleMatch -s named SwitchParameter
text -t 2 string[]
Looking good, now get only parameters starting with i*
PS C:\Scripts> get-params select-string i*
-----------------
- Select-String -
-----------------
name alias position Type
---- ----- -------- ----
include -inc named string[]
inputObject -inp named psobject
Generate a "cheat-sheet" for all cmdlets:
Get-Command | % {get-params $_.name} > c:\AbbreviatedParameters.txt
Some command-lets do not support the parameters property (or globbing) and will render an error:
Get-Help : No parameter matches criteria *.
At line:1 char:9
+ get-help <<<< Get-AuthenticodeSignature -param *
######## UNSUPPORTED CMDLETS ######
Get-AuthenticodeSignature
Get-Credential
Get-Culture
Get-ExecutionPolicy
Get-Host
Get-PfxCertificate
Get-PSProvider
Get-TraceSource
Get-UICulture
Import-Clixml
Import-Csv
Invoke-Expression
Out-Default
Out-Null
Stop-Transcript
Write-Debug
Write-Output
Write-Verbose
Write-Warning
One last thing, PowerShell maintains a short notation for its common parameters:
Verbose {vb}
Debug {db}
ErrorAction {ea}
ErrorVariable {ev}
OutVariable {ov}
OutBuffer {ob}
Here is the code for get-params:
function get-params{
param(
[string]$cmd = $(throw "Please specify cmdlet name"),
[string]$pat="*"
)
$ErrorActionPreference = "SilentlyContinue";
# check the existence of the command-lets.
$check = get-command | ? {$_.CommandType -eq "Cmdlet" -and $_.name -eq $cmd}
if($check -eq $null){
write-warning "No such command [$cmd]";
return;
}
# some command-lets do not support the parametrs property.
$check = @(get-help $cmd -parameter * -ea silentlyContinue).count
if($check -eq $null -or $check -eq 0){
write-warning "No parameters found for [$cmd]";
return;
}
$obj = get-help $cmd -parameter $pat;
$obj | add-Member -memberType noteProperty -name alias -value "" -force;
$params = $obj | % {$_.name}
for($i=0;$i -le $obj.length;$i++){
[bool]$exitFlag = $false;
for($x=0;$x -le $params[$i].length -and !($exitFlag);$x++){
$regex = "^" + $params[$i].substring(0,$x);
if(($params -match $regex).count -eq 1){
$exitFlag=$true;
$obj[$i].alias = ("-"+$regex.substring(1,$regex.length-1)).tolower();
}
}
}
[int]$len="-[$cmd]-".length;
write-host
"-" * $len ; "- $cmd -" ; "-" * $len;
$obj | select Name,Alias,Position,@{n="Type";e={$_.type.name}}| sort name | ft -auto
}
Enjoy!
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