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PowerShell Cheat Sheet

Condition Examples

if ((-not [string]::IsNullOrEmpty($string)))
if (($nr > 5) -and ($string eq ''))

Control Flow

switch ($exitCode) {
    0 { break }
    1 { throw "Error!" }
    2 { throw "Another error!" }
    default { throw "That's unexpected!" }
}

Exceptions

try {
   throw "My exception";
} catch {
   Write-Output "Caught exception!";
}

Functions

function My-Function {
   param (
   [string]$param1,
   [string]$param2
   )
   
   # Code comes here
}

Env Variables

Fetching

$tmp =  $env:SOME_ENV_VAR;

$env:Path = [Environment]::GetEnvironmentVariable('Path',[System.EnvironmentVariableTarget]::Machine);

Setting env var on global level

[System.Environment]::SetEnvironmentVariable('MYVAR','some value', [System.EnvironmentVariableTarget]::Machine)

Filesystem

Building a filename

$filename = Join-Path $directory 'some.exe'

Checking for a file

if (!(Test-Path $myfile -PathType Leaf)) {
}

Create directory

New-Item "$mydir" -ItemType Directory -Force

Removing files/directories

Remove-Item "$somepath" -Force -Recurse

Execution Policies

Set-ExecutionPolicy Bypass -Scope Process -Force
Set-ExecutionPolicy RemoteSigned -Scope CurrentUser

Download by URL

iwr -useb http://example.com/somefile
iwr -useb http://example.com/someexe | iex       # Download and execute it

Check PowerShell Version

if ($PSVersionTable.PSVersion.Major -lt 5) {
    # ...
}

Using a proxy

$env:https_proxy='<server>:<port>'