Demos of writing OS agnostic PowerShell Core scripts

demo_os_agnostic.ps1

# PowerShell remoting over SSH

## Configuring Windows

### Install SSHD as Feature on Demand
### Modify sshd_config for powershell subsystem

## SSH remoting

ssh –l user@domain computer
pwsh

## PowerShell remoting

Enter-pssession -hostname computer -username user@domain
Enter-pssession -hostname user@computer

# PowerShell remoting over WSMan

## Office365 from non-Windows

#### With macOS Mojave use OpenSSL from MacPorts not HomeBrew

$cred = get-credential
$s = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/ -Credential $cred -AllowRedirection -Authentication Basic
Import-pssession $s
Get-mailbox

## Windows from non-Windows

### Setup HTTPS endpoint for WinRM

Set-Item WSMan:\localhost\Service\Auth\Basic $true
Import-WinModule pki
$selfSignedCert = New-SelfSignedCertificate -CertStoreLocation Cert:\LocalMachine\My -DnsName $env:COMPUTERNAME
New-Item -Path WSMan:\LocalHost\Listener -Transport HTTPS -Address * -CertificateThumbPrint $selfSignedCert.Thumbprint
New-NetFirewallRule -DisplayName "Windows Remote Management (HTTPS-In)" -Name "Windows Remote Management (HTTPS-In)" -Profile Any -LocalPort 5986 -Protocol TCP

### WSMan remoting into Windows from non-Windows

$cred = Get-Credential steve

### Use a real cert!  But if using self-signed for testing:
$so = [System.Management.Automation.Remoting.PSSessionOption]::new()
$so.SkipCACheck = $true
$so.SkipCNCheck = $true

Enter-PSSession -ComputerName slee-office -Credential $cred -Authentication Basic -UseSSL -SessionOption $so

## Docker

### Ubuntu 16.04

docker run -it mcr.microsoft.com/powershell:latest
$psversiontable
cat /etc/lsb-release

### Alpine

docker run -it mcr.microsoft.com/powershell:alpine-3.8
cat /etc/alpine-release

# Handling OS differences

## Detecting the OS

$IsWindows, $IsLinux, $IsMacOS

if ($IsMacOS) { "Using macOS" }

## Detecting Windows for both Windows PowerShell and PSCore6

if ($null -eq $IsWindows –or $IsWindows –eq $true) { “Windows!” }

# Case Sensitivity Filesystem and Environment Variables

## Modules - Linux

mkdir TestModule
New-ModuleManifest -Path ./TestModule/testmodule.psd1
Import-Module ./TestModule
mv ./TestModule/testmodule.psd1 ./TestModule/TestModule.psd1
Import-Module ./TestModule

## Casesensitivity - Linux

$env:path
$env:PATH

## Path separator

$env:PSModulePath
$psmodulepath = $env:PSModulePath -split [System.IO.Path]::PathSeparator
$psmodulepath += "CustomModulePath"
$psmodulepath
$psmodulepath -join [System.IO.Path]::PathSeparator

## $env:TEMP vs $env:TMP vs $env:TMPDIR

[System.IO.Path]::GetTempPath()

## Console output improvements

### Easier VT100 escape codes

"`e[5m`e[35mHello `e[1m`e[36mWorld!`e[m"

### Easier Unicode

"PowerShell `e[31m`u{2665}`e[m community `u{1f44d}, Open Source `u{1F44C}, and Linux `u{1F427}!"