Stephen's Wiki

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====== Powershell Cheat Sheet ======

===== File exists check =====

<code powershell>
if (Test-Path $path) {
    Write-Host "File exists."
}
if (!(Test-Path $path)) {
    Write-Host "File does not exist."
}
</code>

===== Check previous command was successful =====

<code powershell>
if ($?) {
	Write-Host 'Success' -ForegroundColor Green
} else {
	Write-Host 'FAILED' -ForegroundColor Red
	throw 'Failed.'
}
</code>

===== Searching in files =====

<code powershell>
Get-ChildItem -Recurse -Path C:\Temp -Include *.txt | Select-String 'This', 'OR that' | Select-String 'AND this' | Format-Table -property path, line -autosize | Out-String -Width 4096
</code>

===== Search and replace in a file =====

<code powershell>
(Get-Content $filename) -replace 'heise', 'Heise' | Set-Content $filename
</code>

===== Create a timestamp =====

<code powershell>
$timestamp = (Get-Date).ToString("yyyyMMdd HHmmssff")
</code>

===== Parameters =====

<code powershell>
param (
    [parameter(Mandatory=$true,HelpMessage='The target server')] [string]$targetServer,
    [parameter(Mandatory=$true)] [string]$targetWebConfig,
    [parameter(Mandatory=$false)] [string]$build = 'debug'
)
</code>

===== Set current directory to script location =====

<code powershell>
Push-Location "$($MyInvocation.MyCommand.Path)\..\"
#...
Pop-Location
</code>

===== Certificates =====

Search by thumbprint:

<code powershell>
Get-ChildItem -Path Cert: -Recurse | Where-Object { $_.Thumbprint -and $_.Thumbprint.ToLower().StartsWith('c4') }
</code>

To check if the cert is valid, pipe it the ''Test-Certificate'' command:

<code powershell>
Get-ChildItem -Path Cert: -Recurse | Where-Object { $_.Thumbprint -and $_.Thumbprint.ToLower().StartsWith('c4') } | Test-Certificate
</code>

To check for expired / revoked certs:

<code powershell>
$certs = Get-ChildItem -Path Cert:\LocalMachine\My -Recurse
foreach ($cert in $certs) {
    Write-Host "$($cert.Thumbprint) $($cert.Subject)"
 
    if ($certs.NotAfter -lt (Get-Date)) {
        Write-Host "    Expired on $($certs.NotAfter)" -ForegroundColor Red
    }
    elseif ($cert | Test-Certificate) {
        Write-Host "    Tested ok." -ForegroundColor Green
    }
}
</code>

===== Get Install-Module working behind a webproxy =====

  - Run ''notepad $PROFILE''.
  - Add this to the top:<code powershell>
# Uncomment this to use PowerShellGet
#$Username="global\heises"
#$Password="password"
#[system.net.webrequest]::defaultwebproxy = new-object system.net.webproxy('http://10.104.66.70:80')
#[system.net.webrequest]::defaultwebproxy.credentials = New-Object System.Net.NetworkCredential($Username, $Password)
#[system.net.webrequest]::defaultwebproxy.BypassProxyOnLocal = $true</code>
  - Uncomment, fill out the details, and save.
  - Start a //new// Powershell session.
  - Run ''Register-PSRepository -Default''
  - Run ''Get-PSRepository'' again to verify.
  - Once installation is complete, comment out commands and change password.

If this doesn't work, and it won't for an ANZ Dev VM, try the [[powershell_manual_module_installation|PowerShell Manual Module Installation]].

===== No Sleep =====

May only work inside Windows Powershell ISE.

<code powershell>
$intervalSeconds = 60
$mouseDistance = 1

$myshell = New-Object -com "Wscript.Shell"
while ($true) {
    Start-Sleep -Seconds $intervalSeconds
    $Pos = [System.Windows.Forms.Cursor]::Position
    [System.Windows.Forms.Cursor]::Position = New-Object System.Drawing.Point((($Pos.X) + $mouseDistance) , $Pos.Y)
    [System.Windows.Forms.SendKeys]::SendWait("{f15}")
    Write-Host 'A shuffle to the right.'
    Start-Sleep -Seconds $intervalSeconds
    $Pos = [System.Windows.Forms.Cursor]::Position
    [System.Windows.Forms.Cursor]::Position = New-Object System.Drawing.Point((($Pos.X) - $mouseDistance) , $Pos.Y)
    [System.Windows.Forms.SendKeys]::SendWait("{f15}")
    Write-Host 'A shuffle to the left.'
}
</code>

===== Text Processing =====

==== Simple replace (supports regexs) ====
<code powershell>
'1234abcd' -replace '\d', '*' # ****abcd
</code>

==== Simple match (supports regexs) ====
<code powershell>
'123.456.789.123' -match '\d+(?:\.\d+){2}' # returns true if there is a match.
$Matches.Values                            # = '123.456.789'
</code>

==== Filter lines by regex ====
<code powershell>
$inputText = '!! Match me
Not me
!! Match me too
Not me tho'
$regex=[regex] '(?m)^!!.+?$'
$regex.matches($inputText) | Foreach-Object { $_.Value } # Returns a string, one match per line.
</code>

==== Reformatting by using regex groups ====

<code powershell>
# Filter lines by regex.
$inputText = ' .. . . left:10 .  .. right:10 ... 
 .. . . left:20 .  .. right:20 ... 
 .. . left:30 . . ...  .. right:30 ... 
 left:40right:40' -replace "`r`n", "`n"

$regex=[regex] '(?m)^[ \.]*(?<left>left:\d+)[ \.]*(?<right>right:\d+)[ \.]*$'
$regex.matches($inputText) | Foreach-Object { $_.Groups["left"].value + ' - ' + $_.Groups["right"].value}
# Returns a string:
#left:10 - right:10
#left:20 - right:20
#left:30 - right:30
#left:40 - right:40
</code>

==== Regex groups ====

<code powershell>
$regex=[regex] ('-rw-rw---- 1 root sdcard_rw (?<length>\d+) (?<date>\d\d\d\d-\d\d-\d\d \d\d:\d\d) (?<filename>.*)$')
$input='-rw-rw---- 1 root sdcard_rw 358 2019-09-01 19:50 /storage/emulated/0/Podcasts/Sync Test/New folder/rua.txt'
$matches = $regex.matches($input)
if (!($matches.Success)) {
	Write-Host "Regex failed to match: $input" -ForegroundColor Red
	Exit(-1)
}
Write-Host "length   = $($matches.Captures.Groups["length"].value)"
Write-Host "date     = $($matches.Captures.Groups["date"].value)"
Write-Host "filename = $($matches.Captures.Groups["filename"].value)"
</code>

==== Regex replace with groups ====

<code powershell>
# $1 = group 1, $2 = group 2, etc.
'123 456 789' -replace '(\d+ )(\d+)( \d+)', '$1!$2!$3'  # = '123 !456! 789'
</code>

==== Pipeline function ====

<code powershell>
function Replace-String {
    [cmdletbinding()]
    Param (
        [parameter(ValueFromPipeline)]
        [string]$Input,
        [string]$OldValue,
        [string]$NewValue
    )

    Process {
        $Input -replace $OldValue, $NewValue
    }
}

'djkslajklfdsjkl' | Replace-String -OldValue 'd' -NewValue 'x'
</code>