PowerShell Windows Patterns

Critical patterns and pitfalls for Windows PowerShell.

1. Operator Syntax Rules

CRITICAL: Parentheses Required

Rule: Each cmdlet call MUST be in parentheses when using logical operators.

2. Unicode/Emoji Restriction

CRITICAL: No Unicode in Scripts

Rule: Use ASCII characters only in PowerShell scripts.

3. Null Check Patterns

Always Check Before Access

4. String Interpolation

Complex Expressions

Pattern:

$value = $obj.prop.sub
Write-Output "Value: $value"

5. Error Handling

ErrorActionPreference

Try/Catch Pattern

• Don't return inside try block
• Use finally for cleanup
• Return after try/catch

6. File Paths

Windows Path Rules

Rule: Use Join-Path for cross-platform safety.

7. Array Operations

Correct Patterns

8. JSON Operations

CRITICAL: Depth Parameter

Rule: Always specify -Depth for nested objects.

File Operations

9. Common Errors

10. Script Template

# Strict mode
Set-StrictMode -Version Latest
$ErrorActionPreference = "Continue"

# Paths
$ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path

# Main
try {
    # Logic here
    Write-Output "[OK] Done"
    exit 0
}
catch {
    Write-Warning "Error: $_"
    exit 1
}

Remember: PowerShell has unique syntax rules. Parentheses, ASCII-only, and null checks are non-negotiable.