How to Use Regex in PowerShell: Syntax and Examples

In PowerShell, you use regex with operators like -match and methods like Matches() to find patterns in text. You write regex patterns as strings and use them to test, extract, or replace text easily.

Syntax

PowerShell uses regex mainly with the -match operator and the Matches() method. The -match operator returns True if the pattern matches the string. The Matches() method returns all matches as a collection.

• string -match 'pattern': Checks if pattern exists in string.
• [regex]::Matches(string, 'pattern'): Finds all matches of pattern in string.

powershell

$text = 'Hello World'
if ($text -match 'World') {
    'Match found'
} else {
    'No match'
}

$matches = [regex]::Matches($text, 'l+')
foreach ($m in $matches) {
    $m.Value
}

Output

Match found
ll
l

Example

This example shows how to check if a string contains digits and how to extract all digit sequences using regex.

powershell

$input = 'Order123 and Invoice456'

# Check if string contains digits
if ($input -match '\d+') {
    'Digits found in string'
}

# Extract all digit sequences
$allMatches = [regex]::Matches($input, '\d+')
foreach ($match in $allMatches) {
    $match.Value
}

Output

Digits found in string
123
456

Common Pitfalls

Common mistakes include forgetting to escape special characters in regex patterns and confusing -match with -like. Also, -match returns a boolean, not the matched text directly.

Use $matches[0] after -match to get the first match text.

powershell

# Wrong: Using -like instead of -match
'abc123' -like '*\d*'

# Right: Using -match with escaped pattern
if ('abc123' -match '\d+') {
    $matches[0]  # Outputs the matched digits
}

Output

False
123

Quick Reference

Operator/Method	Purpose	Example
-match	Check if pattern exists (returns True/False)	'abc123' -match '\d+'
-notmatch	Check if pattern does NOT exist	'abc' -notmatch '\d+'
[regex]::Matches()	Get all matches as collection	[regex]::Matches('abc123', '\d+')
-replace	Replace text matching pattern	'abc123' -replace '\d+', '456'
$matches	Automatic variable holding match info after -match	$text -match 'pattern'; $matches[0]

Key Takeaways

Use the -match operator to test if a regex pattern exists in a string.

Use [regex]::Matches() to find all matches of a pattern in a string.

Escape special regex characters with double backslashes in PowerShell strings.

After -match, use the automatic $matches variable to access matched text.

Avoid confusing -match (regex) with -like (wildcard matching).