How to parse all given arguments in PowerShell - powershell

Question

I want to create a loop function that looks like this:
function Loop { foreach ($File in Get-ChildItem | Select-Object -exp Name) { # Some command } }
It works perfectly fine for simple one-word commands, but it doesn't work for anything else. Of course, I need a way to parse all given arguments, but I don't know how. All documentations that I've been able to understand (I just started working with PowerShell about a week ago) don't seem to have an answer to this.
It would be great if someone could give me a solution to this problem.🙂

Answer 1

Like issuing several commands inside the loop?
#!/usr/bin/env powershell
function script:Loop {
foreach ($File in Get-ChildItem | Select-Object -ExpandProperty Name) {
##Some command
##another command
## a test
Write-Output -InputObject ('The current item is named {0}.' -f $file)
}
}
Loop
output
PS C:\Powershell\Scripts> . "c:\Powershell\Scripts\forloop.ps1"
The current item is named dchero.ps1.
The current item is named findinstaller.ps1.
The current item is named Untitled11.ps1.
The current item is named Untitled5.ps1.
The current item is named Untitled8.ps1.
However you don't really need to do the Select-Object -ExpandProperty Name because Get-ChildItem returns multiple properties for the objects it finds. You can see all of them by piping into Get-Member
PS C:\Powershell\Scripts> Get-ChildItem | Get-Member
TypeName: System.IO.FileInfo
Name MemberType Definition
---- ---------- ----------
Target AliasProperty Target = LinkTarget
LinkType CodeProperty System.String LinkType{get=GetLinkType;}
Mode CodeProperty System.String Mode{get=Mode;}
ModeWithoutHardLink CodeProperty System.String ModeWithoutHardLink{get=ModeWithoutHardLink;}
AppendText Method System.IO.StreamWriter AppendText()
CopyTo Method System.IO.FileInfo CopyTo(string destFileName), System.IO.FileInfo CopyTo(string destFileName, bool overwrite)
Create Method System.IO.FileStream Create()
CreateAsSymbolicLink Method void CreateAsSymbolicLink(string pathToTarget)
CreateText Method System.IO.StreamWriter CreateText()
Decrypt Method void Decrypt()
Delete Method void Delete()
Encrypt Method void Encrypt()
Equals Method bool Equals(System.Object obj)
GetHashCode Method int GetHashCode()
GetLifetimeService Method System.Object GetLifetimeService()
GetObjectData Method void GetObjectData(System.Runtime.Serialization.SerializationInfo info, System.Runtime.Serialization.StreamingContext context), void ISerializab…
GetType Method type GetType()
InitializeLifetimeService Method System.Object InitializeLifetimeService()
MoveTo Method void MoveTo(string destFileName), void MoveTo(string destFileName, bool overwrite)
Open Method System.IO.FileStream Open(System.IO.FileMode mode), System.IO.FileStream Open(System.IO.FileMode mode, System.IO.FileAccess access), System.IO.F…
OpenRead Method System.IO.FileStream OpenRead()
OpenText Method System.IO.StreamReader OpenText()
OpenWrite Method System.IO.FileStream OpenWrite()
Refresh Method void Refresh()
Replace Method System.IO.FileInfo Replace(string destinationFileName, string destinationBackupFileName), System.IO.FileInfo Replace(string destinationFileName,…
ResolveLinkTarget Method System.IO.FileSystemInfo ResolveLinkTarget(bool returnFinalTarget)
ToString Method string ToString()
PSChildName NoteProperty string PSChildName=dchero.ps1
PSDrive NoteProperty PSDriveInfo PSDrive=C
PSIsContainer NoteProperty bool PSIsContainer=False
PSParentPath NoteProperty string PSParentPath=Microsoft.PowerShell.Core\FileSystem::C:\Powershell\Scripts
PSPath NoteProperty string PSPath=Microsoft.PowerShell.Core\FileSystem::C:\Powershell\Scripts\dchero.ps1
PSProvider NoteProperty ProviderInfo PSProvider=Microsoft.PowerShell.Core\FileSystem
Attributes Property System.IO.FileAttributes Attributes {get;set;}
CreationTime Property datetime CreationTime {get;set;}
CreationTimeUtc Property datetime CreationTimeUtc {get;set;}
Directory Property System.IO.DirectoryInfo Directory {get;}
DirectoryName Property string DirectoryName {get;}
Exists Property bool Exists {get;}
Extension Property string Extension {get;}
FullName Property string FullName {get;}
IsReadOnly Property bool IsReadOnly {get;set;}
LastAccessTime Property datetime LastAccessTime {get;set;}
LastAccessTimeUtc Property datetime LastAccessTimeUtc {get;set;}
LastWriteTime Property datetime LastWriteTime {get;set;}
LastWriteTimeUtc Property datetime LastWriteTimeUtc {get;set;}
Length Property long Length {get;}
LinkTarget Property string LinkTarget {get;}
Name Property string Name {get;}
BaseName ScriptProperty System.Object BaseName {get=if ($this.Extension.Length -gt 0){$this.Name.Remove($this.Name.Length - $this.Extension.Length)}else{$this.Name};}
VersionInfo ScriptProperty System.Object VersionInfo {get=[System.Diagnostics.FileVersionInfo]::GetVersionInfo($this.FullName);}
Now that we know what's available we can use them for our scripts.
Like so:
#!/usr/bin/env powershell
function script:Loop {
foreach ($File in (Get-ChildItem)) {
##Some command
##another command
## a test
Write-Output -InputObject ('The current item is named {0}.' -f $file.Name)
Write-Output -InputObject ('The current items size it {0}.' -f $file.Length)
Write-Output -InputObject ('The current items hashcode is {0}.
' -f $file.GetHashCode())
}
}
Loop
Output
PS C:\Powershell\Scripts> . "c:\Powershell\Scripts\forloop.ps1"
The current item is named dchero.ps1.
The current items size it 755.
The current items hashcode is 31624384.
The current item is named findinstaller.ps1.
The current items size it 236.
The current items hashcode is 55386574.
The current item is named forloop.ps1.
The current items size it 466.
The current items hashcode is 50677768.
Finally you can get fancy and make changes to the objects or test them.
#!/usr/bin/env powershell
function script:Loop {
foreach ($File in (Get-ChildItem)) {
## command /argument 1
if ($file.Name -like "*.ps1") {
<# Action to perform if the condition is true #>
Write-Output "We've got a Powershell script here!"
Write-Output "The script is named $file.name"
}
else {
Write-Output "This ain't a Powershell script."
Write-Output "It's named $file.name"
}
## command / arugment 2
$newname = $file.BaseName + "-modifiedbyscript" + $file.Extension
Rename-Item -Path $file.FullName -NewName $newname -WhatIf
}
}
Loop

Answer 2

This might be a hard guess, if it has nothing to do with what you're looking for let me know and I'll delete this answer. If it has something to do with what you're looking I can understand why it could be "hard to explain".
function ThisThing {
[CmdletBinding()]
param(
[parameter(Mandatory, ParameterSetName = 'Expression')]
[scriptblock] $Expression,
[parameter(Mandatory, ParameterSetName = 'Condition')]
[scriptblock] $Condition,
[parameter(Mandatory, ValueFromPipeline, Position = 0)]
[object[]] $InputObject
)
process {
if($PSCmdlet.ParameterSetName -eq 'Expression') {
if($MyInvocation.ExpectingInput) {
return & $Expression
}
$InputObject | & {
process {
& $Expression
}
}
}
else {
if($MyInvocation.ExpectingInput) {
return & { if(& $Condition) { $_ } }
}
$InputObject | & {
process {
if(& $Condition) { $_ }
}
}
}
}
}
A few examples to test the function:
ThisThing (0..10) -Expression {
[pscustomobject]#{
Input = $_
}
}
Get-ChildItem | ThisThing -Expression {
if($_.CreationTime -lt (Get-Date).AddDays(-30)) {
[pscustomobject]#{
CreationDate = $_.CreationTime
Path = $_.FullName
}
}
}
Get-Process | ThisThing -Condition { $_.Name -eq 'svchost' }
ThisThing (Get-Service) -Condition { $_.Status -eq 'Stopped' }