#Variables

• Declaration and assignment:

  $name = 'Alice'
  $count = 10
  $price = 12.5
  $null  # Null value
• Scope:
  • Local/Script/Global/Private, commonly used for controlling variable visibility between functions and scripts
• Common automatic variables:
  • $_ (current pipeline object), $PSVersionTable, $Args, $Error, $PID, $LastExitCode
• Read environment variables: $env:Path; Set: $env:MyVar = 'value'
• Interpolation and subexpressions:
  • String interpolation: "Hello $name"
  • Subexpressions: "2+2=$(int)"

Type constraints and type casting:

[int]$count = '42'     # Automatically converts to int
[datetime]$d = '2024-01-01'

Tip: Avoid abusing variables in global scope; pass data between functions through parameters and return values to improve maintainability.