Operators

1. Arithmetic Operations

• + - * / % basic arithmetic
• Power: [math]::Pow(2,10) (.NET method)
• Increment/Decrement: $i++, --$i

2. Comparison Operations (type and case sensitive)

• General comparison: -eq -ne -gt -ge -lt -le
• Case-sensitive: Add c before comparison operator, e.g., -ceq -cne
• Case-insensitive (default): Add i, e.g., -ieq -ine (same as default string comparison)

3. Wildcard and Regular Expressions

• Wildcard matching: -like, -notlike (* ?)
• Regex matching: -match, -notmatch, after matching $Matches automatic variable saves groups

4. Containment and Collections

• Array contains: -contains (left operand is collection, checks if it contains the right "element")
• Reverse contains: -in (right side is collection)
• Subset checking: Compare-Object or use set operations (see below)

5. String Operations

• Concatenation: 'a' + 'b' or interpolation "$a$b"
• Repetition: 'a' * 3 # 'aaa'

6. Logical and Bitwise Operations

• Logical: -and -or -not (short-circuit evaluation)
• Bitwise: -band -bor -bxor -bnot -shl -shr

7. Assignment and Compound Assignment

• Basic: =
• Compound: += -= *= /= %=

8. Type and Conversion

• Type checking: -is -isnot
• Try conversion: -as (returns $null on failure)

9. Redirection and Pipeline

• Pipeline: | passes objects to the next command
• Output redirection (text): > >> 2> 2>> *>> etc.
• Out-File/Set-Content/Add-Content provide encoding and append control

10. Compare Objects and Sorting

Compare-Object (1,2,3) (2,3,4)           # Difference comparison
1,5,3 | Sort-Object                      # Sorting (stable)
Get-ChildItem | Sort-Object Length -Desc

11. Pattern Matching Shortcuts

switch -Wildcard ($name) {
  'ab*' { 'starts with ab' }
  default { 'no match' }
}

switch -Regex ($text) {
  '^(?<letter>[a-z])' { $Matches.letter }
}

12. Common Pitfalls

• Distinguish -contains and -like: the former is "collection contains element", the latter is "string wildcard matching".
• -eq comparing arrays with scalars: compares item by item and returns boolean array, may cause unexpected results in if statements; use -contains/-in instead.
• String comparison is case-insensitive by default, use -ceq/-cne for exact matching.