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not a substringUnderstand that .Trim('abc') removes any combination of 'a'

Trim In PowerShell: CLI Command Reference, Syntax, Flags

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trim in powershell is the .NET String.Trim() method that removes leading and trailing whitespace or specified characters. It includes TrimStart() and TrimEnd() variants for targeted removal.

# Basic syntax
$string.Trim()
$string.Trim([char[]]$CharactersToRemove)
$string.TrimStart([char[]]$CharactersToRemove)
$string.TrimEnd([char[]]$CharactersToRemove)

# Alternative using -replace regex
$string -replace '^s+|s+$'   # trim whitespace
$string -replace '^[chars]+|[chars]+$'  # trim specific chars

Tested on Windows PowerShell 5.1 and PowerShell 7.4 (cross-platform).

Syntax

Full syntax from official docs: .Trim([ Characters_to_remove ]), .TrimEnd([ Characters_to_remove ]), .TrimStart([ Characters_to_remove ]). If Characters_to_remove is omitted, whitespace is removed. Multiple characters can be specified; order does not affect result.

Options and Flags

Parameter / Method Type Default Description
.Trim() Method Whitespace Removes all Unicode whitespace from both ends (spaces, tabs, newlines, etc.)
.Trim([char[]]) Method N/A Removes any characters present in the array from both ends. Order ignored.
.TrimStart([char[]]) Method Whitespace Same as Trim() but only from the start of the string.
.TrimEnd([char[]]) Method Whitespace Same as Trim() but only from the end of the string.
-replace operator Operator N/A Supports regex patterns like '^s+|s+$' for advanced trimming; not a method but commonly used.

Usage Examples

Example 1: Remove leading/trailing whitespace from user input

$userInput = "   John Doe   "
$clean = $userInput.Trim()
Write-Output "'$clean'"   # Output: 'John Doe'

Default .Trim() removes all Unicode whitespace from both ends — the most common sanitization before comparisons or storage.

Example 2: Remove trailing backslashes from a directory path

$path = "C:UsersAdminDocuments"
$normalized = $path.TrimEnd('')
Write-Output $normalized   # Output: C:UsersAdminDocuments

Trailing backslashes break path concatenation; .TrimEnd('') removes only trailing while preserving the path structure.

Example 3: Trim multiple characters from both ends

$text = ""***Alert*** System overload! ***""
$cleaned = $text.Trim('*'