REGEXVAULTv2.0
Dev & Systems/File Paths
Verified Safe

Windows Absolute Path (Drive Letter) Regex for Go

/^[a-zA-Z]:(?:\\{1,2}|\/)(?:[^\\/:*?"<>|\r\n]+(?:\\{1,2}|\/))*[^\\/:*?"<>|\r\n]*$/

What this pattern does

This page provides a well-structured, multi-part regular expression for matching windows absolute path (drive letter), ported and verified for Go. A rigorously tested regex reduces debugging time and protects your application from edge-case failures. The snippet below is ready to drop into your Go project — whether you're validating in a Gin handler, a gRPC service, or a command-line tool.

Go Implementation

Go
// Windows Absolute Path (Drive Letter)
// ReDoS-safe | RegexVault — Dev & Systems > File Paths

package validation

import "regexp"

var windowsAbsolutePathDriveLetterRe = regexp.MustCompile(`^[a-zA-Z]:(?:\\{1,2}|\/)(?:[^\\/:*?"<>|\r\n]+(?:\\{1,2}|\/))*[^\\/:*?"<>|\r\n]*$`)

func ValidateWindowsAbsolutePathDriveLetter(s string) bool {
    return windowsAbsolutePathDriveLetterRe.MatchString(s)
}

// Example
// fmt.Println(ValidateWindowsAbsolutePathDriveLetter("C:\\Users\\user\\Documents")) // true

Test Cases

Matches (Valid)
Rejects (Invalid)
C:\\Users\\user\\Documents/usr/local/bin
D:\\Projects\\myapp\\srcUsers\\Documents
C:/Windows/System32C:\\path<invalid>
E:\\Data\\2024\\report.xlsxC:\\path*star
C:\\

When to use this pattern

This pattern is drawn from the Dev & Systems > File Paths category and carries a ReDoS-safe certification. That matters for Go developers because Go's RE2 engine is inherently safe from catastrophic backtracking, but this pattern has been additionally verified for correctness. RegexVault audits patterns against known backtracking attack vectors, ensuring you have the necessary context before using this regex in a high-stakes production environment.

Common Pitfalls

Windows device namespaces (\\\\?\\C:\\path) can bypass path length limits and security checks. Reject paths starting with \\\\ if only regular drive-letter paths are expected.

Technical Notes

Windows reserved characters < > : " | ? * are excluded. The pattern accepts both backslash and forward slash. Drive letters are A-Z. UNC paths (\\\\server\\share) require dev-path-06.

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