💠

# Declare variable
$name = "John"
$age = 25
$pi = 3.14
$isValid = $true

# Type casting
[int]$number = "42"
[string]$text = 123
[datetime]$date = "2024-01-01"

# Get variable type
$name.GetType()

# Create array
$arr = @(1, 2, 3, 4, 5)
$arr = 1..10  # Range

# Access elements
$arr[0]       # First
$arr[-1]      # Last
$arr[0..2]    # First 3

# Operations
$arr += 6     # Add element
$arr.Count    # Length
$arr | ForEach-Object { $_ * 2 }

# Create hashtable
$hash = @{
  Name = "John"
  Age = 25
  City = "NYC"
}

# Access values
$hash["Name"]
$hash.Name

# Add/Update
$hash["Country"] = "USA"
$hash.Remove("City")

# Iterate
$hash.GetEnumerator() | ForEach-Object {
  "$($_.Key): $($_.Value)"
}

# String interpolation
$name = "World"
"Hello, $name!"           # Interpolated
'Hello, $name!'           # Literal

# Here-strings
$text = @"
Multi-line
string here
"@

# String methods
$str.ToUpper()
$str.ToLower()
$str.Replace("old", "new")
$str.Split(",")
$str.Trim()
$str.Contains("sub")

if ($x -gt 10) {
  "Greater than 10"
} elseif ($x -eq 10) {
  "Equals 10"
} else {
  "Less than 10"
}

# Comparison operators
# -eq  Equal
# -ne  Not equal
# -gt  Greater than
# -lt  Less than
# -ge  Greater or equal
# -le  Less or equal
# -like  Wildcard match
# -match  Regex match

switch ($value) {
  1 { "One" }
  2 { "Two" }
  3 { "Three" }
  default { "Unknown" }
}

# With wildcard
switch -Wildcard ($file) {
  "*.txt" { "Text file" }
  "*.ps1" { "Script file" }
}

# With regex
switch -Regex ($text) {
  "^\d+$" { "Numbers only" }
  "^\w+$" { "Word chars" }
}

# For loop
for ($i = 0; $i -lt 10; $i++) {
  $i
}

# Foreach loop
foreach ($item in $collection) {
  $item
}

# ForEach-Object (pipeline)
1..10 | ForEach-Object {
  $_ * 2
}

# Parallel (PowerShell 7+)
1..10 | ForEach-Object -Parallel {
  $_ * 2
} -ThrottleLimit 5

# While loop
while ($x -lt 10) {
  $x++
}

# Do-While
do {
  $x++
} while ($x -lt 10)

# Do-Until
do {
  $x++
} until ($x -ge 10)

# Break and Continue
foreach ($i in 1..10) {
  if ($i -eq 5) { continue }  # Skip
  if ($i -eq 8) { break }     # Exit loop
  $i
}

function Say-Hello {
  param(
    [string]$Name = "World"
  )
  "Hello, $Name!"
}

Say-Hello -Name "John"

function Get-Square {
  [CmdletBinding()]
  param(
    [Parameter(Mandatory=$true, ValueFromPipeline=$true)]
    [ValidateRange(1, 100)]
    [int]$Number
  )

  begin {
    # Run once before pipeline
  }

  process {
    # Run for each pipeline item
    $Number * $Number
  }

  end {
    # Run once after pipeline
  }
}

1..5 | Get-Square

function Get-Data {
  $result = @()
  $result += "Item 1"
  $result += "Item 2"
  return $result
}

# Multiple outputs
function Get-Info {
  [PSCustomObject]@{
    Name = "John"
    Age = 25
  }
}

# Enable remoting (admin)
Enable-PSRemoting -Force

# Connect to remote
Enter-PSSession -ComputerName Server01

# Run command remotely
Invoke-Command -ComputerName Server01 -ScriptBlock {
  Get-Process
}

# Multiple computers
Invoke-Command -ComputerName Server01, Server02 -ScriptBlock {
  $env:COMPUTERNAME
}

try {
  # Code that might fail
  Get-Content "nonexistent.txt" -ErrorAction Stop
}
catch {
  # Handle error
  Write-Error "Error: $_"
  $_.Exception.Message
}
finally {
  # Always runs
  "Cleanup"
}

# Error action preference
$ErrorActionPreference = "Stop"  # Stop, Continue, SilentlyContinue, Inquire