REGEXVAULT
Dev & Systems/Shell
ReDoS Checked

Shebang Line Regex for Go

/^#!(/(?:[a-zA-Z0-9._\-]+/)*[a-zA-Z0-9._\-]+)((?:\s+[^\s]+)*)$/

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What this pattern does

This page provides a well-structured, multi-part regular expression for matching shebang line, 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
// Shebang Line
// ReDoS-checked | RegexVault — Dev & Systems > Shell

package validation

import "regexp"

var shebangLineRe = regexp.MustCompile(`^#!(/(?:[a-zA-Z0-9._\-]+/)*[a-zA-Z0-9._\-]+)((?:\s+[^\s]+)*)$`)

func ValidateShebangLine(s string) bool {
    return shebangLineRe.MatchString(s)
}

// Example
// fmt.Println(ValidateShebangLine("#!/bin/bash")) // true

Test Cases

Matches (Valid)
Rejects (Invalid)
#!/bin/bash#! /bin/bash
#!/usr/bin/env python3# comment
#!/usr/bin/env node --experimental-vm-modules/bin/bash
#!/bin/sh#!/
#!/usr/bin/perl -w!#/bin/bash

When to use this pattern

This pattern is drawn from the Dev & Systems > Shell category and has been checked for ReDoS risk. 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

#! with a space before the path is supported by some kernels but not all. Avoid the space for maximum compatibility.

Technical Notes

Groups: 1=interpreter path, 2=arguments. The env idiom (#!/usr/bin/env python3) is preferred for portability. The shebang must be the first two characters of the file.

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